Aquarium Myths and Misinformation

[Doctorgori]

As a member of the tang police, I was enthusiastically nodding my head in agreement while reading the section on huge fish thriving in small tanks.

Reminded me of another common myth: People with purple/scopas/hippo/etc. tangs in a 40g breeder actually getting a bigger tank or rehoming the fish when it’s time (if at all).

The demise of the “Tang Police” has been a disservice…I see newbies “Stocking list” and I just bite my lips because the “re-homing” advice they get IMHO is madness…IME tangs can grow fast and need swimming room…its not just a bio-load thing …folks should go to the Caribbean and see just how large Atlantic Blue tangs and doctorfish get…

@Jay Hemdal can you please elaborate a bit more on the use of UV? Did I understand correctly that it does nothing for the free floating stages of Ick and Velvet? I mainly use UV to try and mitigate potential disease outbreaks...

Thanks!

about to ask that also

It addresses free floating organisms and what passes through the unit- Not what is pre-existing

Appreciate the clarity…

While we are playing “Mythbusters” I want to add to that ……
I don’t fully trust UV alone to eradicate anything. I had a horrible ich out break not 2 months ago loosing that 1 in 20 RARE rock beauty that actually fed with gusto and didn’t eat corals… This outbreak happened soon after my Apex shut off the UV and didn’t turn it back on…Appears ich was always in the tank, just controlled or kept in check by the UV..uh maybe….
…As to Peroxide and “Mythbusters”
…I give it the same skepticism and use/treat it similar to UV…I don’t think it eradicates anything per se, used alone, but I do suspect it sorta knocks the “numbers” down…also just my opinion, but I think it only worked for me at the higher than recommended levels and used in conjunction with “Medic” …no formal study, just anecdotal suspicion….

 

[Freenow54]

Aquarium Myths and Misinformation

c. 2023 Jay Hemdal


Over the last 50 years, I’ve heard a number of myths and possible misinformation applied to aquariums and the husbandry of the animals contained in them. Most of these seem to go unchallenged; at least they keep showing up online, long after they have been shown to be incorrect.

Some of these myths take on the same characteristics as “urban legends” (Such as the story of the child who gave her hamster a bath and then used a microwave oven to dry it off – with explosive results!). These are stories that people hear and believe “that it must be true because their friend knew a person whose sister actually saw it happen”. The true source of these stories can never actually be tracked down, and most are not based in fact – although the most successful myths and legends always have a small kernel of truth to them.

I’ll admit the sticking point here is that I’m asking you to accept my de-bunking of these myths with just a little more evidence than is present in the myths themselves! I also realize that not everyone will agree with my assessment of some of these issues. I do ask those who do disagree, to reflect on why they do, some of these beliefs are so firmly entrenched in the hobby that people tend to hold them a lot more dearly than the evidence would indicate they should. At the very least I challenge you to always question unsubstantiated claims, they may turn out valid in the end, but many of them are eventually relegated to the realm of myths. Remember, it is the responsibility of the person making fantastic claims to prove their statements are correct, not the other way around. For example, you might hear somebody claim that they saw a U.F.O. If you don’t believe them, it is not your duty to prove them wrong, they must supply evidence to support their claims.

76 day fallow period (or longer) for marine ich, Cryptocaryon: Published in a paper where the co-author was also the editor for the journal. The original study was from a PhD thesis that isn’t widely available. 45 to 60 days at 81 degrees F. is a more reasonable, but still effective fallow period. Fallow periods for other disease are different.

Adding vitamins or food additives to the aquarium’s water: This just feeds the heterotrophic bacteria. Aquatic animals, if they uptake it at all, do so slower than the bacteria do.

Aquariums can hold a set number of inches of fish per gallon: You see this time and time again; “An aquarium’s holding capacity is 2” of fish per gallon”. Sometimes the number differs, in other cases the author adds refinements to the equation to take into account the aquarium’s surface area, filtration method, even water temperature. In every case, the equation has the same fatal flaw: With all else being equal, the waste output of fish, and their subsequent bio-load is not based primarily on the length of the fish, but more so their mass. An easy way to see this is to try to visualize the common formula of “two inches of fish per gallon”. Certainly, a ten gallon aquarium can safely house 20, one inch long guppies. Now, even though the “inches of fish” are equal, try adding one 20” long Pacu to the same tank and see what happens! As the length of a fish increases in a linear fashion, its mass, (and subsequent bio-load) increases by the length raised to the third power, multiplied by a constant (which varies for differently shaped fish). Another variable which also affects bio-load independent of the length of the animal is a given species innate metabolic rate; some species are more active, consume more food and thus produce more waste products than others of the same size.

Avoiding temperature shock is the main reason for acclimating fish: A variety of acclimation techniques have been presented over the years, all with the hoped-for result of reducing stress and shock to an aquarium animal being moved from one aquarium to another. Some people have embraced this idea and taken it to the extreme. There was the aquarium keeper who would float bags for fish in his tank for eight hours rather than the 30 minutes recommended by the pet store; the reasoning given was “in order to expose the fish to the slowest possible change in temperature”. Never mind that in this case, the water temperature in the bag was fully equilibrated with that of the aquarium within the first ten minutes. Even if fish were exposed to a sudden change in water temperature, just how harmful would that be? As a SCUBA diver, watching fish swimming up and down along a ten degree thermocline with apparent impunity makes me wonder. I’ve even seen a damselfish diligently guarding its nest along an 8 degree thermocline in the Galapagos Islands. The continually changing water temperature affected neither the fish nor its eggs. Overly long acclimation times do more harm than good. Take the example of fish, which have been in their bags for over 24 hours. Typically, the pH of their water will be very low, while the ammonia concentration will be high. As it turns out, ammonia is much less toxic to fish at a low pH. Imagine what happens to those fish during a lengthy acclimation; as the carbon dioxide is driven out of the shipping bags, the pH rises. Even though the aquarist is slowly adding tank water to the bag, it isn’t happening fast enough to dilute down the ammonia before the rising pH makes the ammonia toxic enough to kill the fish right in the bags. In other cases, the stress imposed on certain shy fish by restraining them in a clear bag at the surface where they cannot hide is greater than just releasing them so they can seek a secure hiding place. Acclimation times of more than 30 minutes are unnecessary and potentially do more harm than good. The only criteria that MUST be managed carefully is exposing fish to a rise in salinity/specific gravity. This must be done very slowly, or better yet, in stages, by changing the salinity of the tank itself.

Dietary supplements as a “medication”: The best diet in the world will not stop active infections – this is called the “chicken soup” syndrome. A proper diet is of course important for long-term fish health, it's just that changing to "great diet" will not stop active disease. Give this the logic test: will feeding your dog a great diet keep it from getting ticks or fleas? Of course not.

Drip acclimating shipped fish: Not if there is high ammonia. Best to match the temperature, pH and salinity and move the fish directly over and then acclimate them (with no ammonia) to your tank.

Feeding Peas to cure swim bladder issues: The recommendation of "feeding peas" has a long and convoluted history. It began as a treatment for issues with floating fancy goldfish. An aquarist at the Shedd Aquarium promoted this remedy back in the 1960’s and it does work. However, the issue with fancy goldfish is because they have weirdly shaped intestines that trap gas, making them float. Feeding peas works as a laxative, expelling the gas and allowing the fish to swim normally. At some point, this idea got "transferred" to marine fish with swim bladder problems. Feeding peas has NO benefit for swim bladder issues at all, yet the idea has been spread all over the Internet.

Fish only grow in size to fit their aquarium: Most intermediate and advanced aquarists, (or anyone who has ever purchased a Pacu) knows this statement is more accurately stated as: “Fish grow rapidly to a maximum size for that aquarium, then the growth rate slows a bit, but they still outgrow that aquarium if it is in their genetic makeup to grow that large”. Of course, the irony of this seems to be that this slowing of the growth rate only gives the aquarist time to save up money for a larger tank. When the purchase is made and the fish is placed in its spacious new quarters, its growth rate again speeds up until it again is about to outgrow its new tank!

Flying gurnards taking to the air: These bottom dwelling fish were pictured by early naturalist artists as being capable of gliding through the air like flying fish. In reality, these fish extend their huge pectoral fins in an attempt to make themselves look too large to eat by potential predators. As recently as 1976 an eminent fish taxonomist wrote that these fish are “supposedly capable of gliding short distances”. If one considers jumping out of a tank onto the floor as “gliding a short distance” then perhaps this is true, otherwise we should consider this myth dead and buried.

Flying hatchet fish: This is a rather “slippery” tale. Every once in a while, I’ll come across a reference regarding the flying ability of the South American hatchet fish. That’s right, I said FLYING not just gliding. Apparently, the argument is made that the deep breasts of these fish serve as anchor points for huge pectoral muscles, which the fish uses to vibrate its fins and achieve a sort of powered flight. One description I read told of a school of these fish taking to the air and passing by the observer’s head making a loud buzzing sound. Although these fish are well known for their ability to jump out of tanks, I’ve never seen any direct evidence of powered flight. Perhaps they need a longer runway for takeoff? I’ve toyed with the idea of adding a school of these fish to a 20,000 gallon reservoir, and then give them a scare and see if they will fly under those conditions.

Huge fish thriving in a small aquarium: From time to time, I get reports such as a three foot long snakehead living in somebody’s one foot wide by four foot long 55 gallon aquarium. As I’ve previously mentioned, the “fish growing only to a size to fit the tank” statement is a myth, as these reports seem to bear out. Either these fish have an amazing ability to survive in horrendously undersized aquariums, or people’s ability to judge the true size of their fish is impaired, or a combination of both. That recalls the story of the “Florida tape measure”. It seems that some fish dealers have in their possession a magical tape measure: nurse sharks always tape out at 14” – even if they measure 24” when you pick them up at the airport. For other species such as angelfish, the same tape measure that the collector used on the nurse shark will give them a measurement of 8” for a show-sized queen angelfish that ends up being about the size of a half dollar when you unpack it.

Iodized salt is harmful to fish: After selling non-iodized aquarium salt in pet stores for 15 years, I strongly disagreed with the person who first proposed to me that iodized table salt worked just as well as the more expensive “aquarium salt”. Everyone “knew” that the iodine would kill the fish. I had a difficult time believing that this basic tenet of freshwater aquariums was false, but it is. You can safely add the same amount of regular table salt to an aquarium as you would non-iodized aquarium salt.

Lee Chin Eng Natural system: I remember seeing the photographs of Mr. Eng’s tank in hobbyist publications in the early 1970’s and wondering why I could not re-create a similar aquarium. He was reportedly able to keep all manner of fish, corals and other invertebrates in aquariums with just a slow trickle of air. Mr. Eng has evidently passed away, so we only have his photographs to document his systems. I would urge people to study those photographs very closely; quite a bit can be deduced from them by careful observation: A lot of the photos show huge numbers of shrimpfish along with damselfish, clownfish and batfish. Anyone who has successfully kept shrimpfish knows that they do best if fed live mysid shrimp and cannot compete against other fish for live food. My strong opinion is that Mr. Eng added these shrimpfish a short time before taking the photo – and may have done the same with some of the more delicate invertebrates in the tank. Other pictures show corals placed in unnatural positions, showing no evidence of any in-situ growth. Many of the other organisms are hardy species (at least for the short term) such as feather dusters, carpet anemones and red starfish. My hunch is that Mr. Eng set up aquariums with live rock and hardy animals, and then just prior to being photographed, he “spruced the tanks up” by adding a few showy, but delicate species.

Mangrove seedlings help maintain marine aquarium water quality: I can’t recall how many dead and dying mangrove seedlings I’ve recently seen offered for sale, floating jammed into pieces of Styrofoam in dealer’s holding tanks. Keeping mangroves healthy in aquariums is not a simple matter; they are prone to developing scale insect diseases and require very high light levels. Even if the plants do thrive, the argument that they will actively remove organic waste products from the aquarium’s water is difficult to prove. In one case, a 200-gallon exhibit containing three large, actively growing mangrove trees had been set up for two years. It did have a fairly heavy bio-load of fish, but an orthophosphate reading of 7.5 mg/l was totally unexpected based on the supposed nutrient removal ability of mangroves.

Mixing medications with focus + food: This cannot work unless you calculate the dose properly. General Cure should not be dosed orally, as the two components have two different oral doses. This article discusses that: https://www.reef2reef.com/ams/proper-dosing-of-medicated-foods.780/

Mortality caused by medications, years after application: Copper, formalin and cyanide have all been implicated in fish loss years after exposure – this is not borne out by histopathology or veterinary necropsy. Public aquariums all have comprehensive, proactive quarantine/treatment protocols, yet they have some of the longest-lived fish. I've done three studies since 1983 that all show that latent cyanide mortality (while often severe) always manifests itself within 30 to 50 days of exposure. Long term copper exposure has been shown to cause damage to fish, but this is ionic, not chelated copper, and the toxicity appeared during or shortly after the copper exposure.

Nitrite is toxic to marine fish: Ammonia is highly toxic to marine fish at a high pH, but the salts in the water completely de-toxify nitrite ions for marine fish. Nitrite IS deadly to freshwater fish, unless some salt is added to the water.

Predatory fish, which will only accept live foods: I remember in the 1970’s, thinking that lionfish would only eat living fish. Sure enough, all my lionfish would greedily accept “feeder fish” from the very start and would always steadfastly refuse anything else once they have become accustomed to that diet! This was really just a case of a self-fulfilling prophecy, I expected them to eat only goldfish and sure enough, that’s what they became accustomed to! There are a variety of reasons why non-living foods may be preferable; lower cost, ease of storage, ability to supplement with vitamins, etc. Can every species of fish be “trained” to feed on non-living food? It seems that almost any species can, if the required amount of effort is made. The basic trick seems to be to begin feeding the fish an acceptable living food, but very soon after, begin inter-mixing some freshly killed individuals of the same food. As soon as possible, switch the animal over to all dead food, then begin offering slivers of the prepared food made the same size and shape as the accepted prey item. This technique works very well for anglerfish, lionfish and even trumpetfish. In some cases, though, the training effort is simply too great (such as with shrimpfish, seadragons and leaf fish). I once had a report that a person had gotten their seahorse to feed on flake food using this method, but I never saw this firsthand, and would hate to create another myth by putting too much stock in that story!

Ramp up medications slowly: Too many fish die from disease if you take too long, dealers don’t do this, should you? (the only exception is salt when you are raising the salinity or the old ionic copper/citric acid solutions).

Red-rimmed batfish feeding on bananas: Years ago, a person wrote an article for his local aquarium club recalling his experience feeding bananas to a pair of red-rimmed batfish (Platax pinnatus). His argument was that since batfish are residents of mangrove swamps, they should be well adapted to feeding on plant material. By that same train of thought, lions should be well adapted for feeding on grass because they are found in the grasslands of Africa. In addition, the red-rimmed batfish is a resident of deeper coral reefs; it is the round batfish, (Platax orbicularis) which is found as juveniles in mangrove areas. I’ll admit, I have tried feeding bananas to red-rimmed batfish on three occasions (but have never gotten one to accept any). As the article goes on, the author reports that the fish grew to a height which was 2” taller than the aquarium he reported keeping them in – it’s possible that the entire article was some sort of practical joke. The danger is that this article still gets referred to once in a while, it is archived in an on-line computer database, and people keep finding it when they run a search for information about this species.

Small aquariums are inherently less stable than larger ones: I love this myth! It’s one that every aquarist “knows is true” and has been around since long before the advent of thermostatically controlled heaters but should have been dropped once those devices were developed. You see, the only parameter, which is more variable in smaller aquariums than larger ones, is the effect that ambient air temperature has on unheated water. Small tanks will cool down quicker and heat up faster than larger tanks. Once thermostatic heaters were invented, this simply didn’t matter anymore. Take the case where you have two aquariums, and the only variable is their size – they have comparable filtration and other life support equipment (appropriately sized for each tank). If you then compare a ten gallon aquarium, which is housing “X” grams of biomass per gallon and 100 gallon aquarium housing the same ratio of biomass to volume, the biological stability of the two systems will be identical. This myth got its start in unheated tanks, but two other underlying problems have fueled it over the years. Notice that I said that the two tanks need to have comparable life support equipment. Very often, smaller aquariums have cheaply made filters and heaters, which negatively affect the overall stability of the system. In addition, it is much, much easier to overcrowd a smaller aquarium than it is a larger one; adding an extra 2” long swordtail to an already over-crowded ten gallon aquarium might increase the total bio-load of the system by 20%. The same fish being added to a similarly crowded 100 gallon aquarium would increase the total bio-load by perhaps 2%. The relative instability of these smaller tanks can often be documented, but the root of the problem is not directly correlated with the size of the tank.

Snapping shrimp can break aquarium glass when they snap their claws: I first heard this when I was about 12, when I purchased a small snapping shrimp and was warned by the salesperson that they “have been known to crack the glass of tanks”. After adding the shrimp to a small aquarium in my bedroom, I had a rough couple of nights, jumping up to check the tank every time I heard a snap. The glass never broke, nor have I heard any firsthand accounts of this phenomenon (it’s always, “It happened to a friend of mine’s brother). There are reports of snapping shrimp stunning fish which swim by, so there is apparently some force behind their “pop”, just not enough to crack glass.

“Stray voltage” causes fish loss or health issues: This is a red herring, stray or induced voltage (typically < 50 VAC) has no measurable effect on aquarium fish, as they are not grounded, so there is no electrical potential. Stray voltage has been ruled out as a cause of HLLE. True electrical shorts can harm or kill fish, as well as people. All aquariums must be plugged into GFI circuits.

Tank Transfer Method (TTM): This method does work, but in my opinion, it works best for ich (Cryptocaryon) and not for egg laying flukes at all. It can be very rough on fish due to ammonia and excessive handling, and already stressed fish being housed in buckets. Remember that lateral viewing of new fish is a vital tool for diagnosis. Top down views in buckets or totes do not give you a good enough view of how the fish is doing. Then, just when is TTM useful given the logistics of treating diseases? If you use it as part of a quarantine process, you still need a single tank to run the fish through additional quarantine for flukes. If your DT develops ich and you want to use TTM, you can't do that and just put the fish back into the DT, the ich will still be active. That means you would run TTM, but then need to move the fish to another tank during the proper fallow period for the main display aquarium.

Ultraviolet Sterilizers eliminate diseases from aquarium water: Ultraviolet units have absolutely no effect on disease organisms, which live on the fish directly and do not need to leave the fish during some part of its life cycle (some protozoans, trematodes and most pathogenic bacteria). Other parasites such as larger protozoans and all multicellular parasites too big to be killed by aquarium-sized UV units. The expected benefits from a properly operating UV sterilizer would be a lowering of the free-floating bacterial and protozoan populations, as well as fairly good control (close to 100%) of these organisms when water flowing from one tank to another first passes through the UV sterilizer. Side-stream sterilization, where the irradiated water is returned to the same tank is was taken from is always less than 100% effective – too many of the target organisms are able to escape passing through the unit and are able to continue to reproduce.

Using RODI and no aeration for FW dips: Use aerated, pH and temperature balanced water in all cases. Tap water is fine!

Using black mollies as “canaries in a coal mine”: Really only screens for ich, Cryptocaryon, and can introduce euryhaline (brackish water) trematodes into the system, as well as internal parasites carried by the non-quarantined mollies.

###

As to stray voltage. I totally agree with your statement of the fish not being grounded which is necessary to turn anything into a " load "to kill it However have you ever been part of a circuit and not grounded? You can certainly feel the potential in your body. I have learned for an absolute fact that a simple GFI outlet even with a bar with surge protection is simply not enough to prevent house fires. A GFI simply measures Amperage in and returning and opens the circuit with a very small difference which I forget. All of the numbers along with how much amperage it takes to kill a human are available . I will happily provide facts if anyone wants . It is way less than an amp. I experienced another truth for myself. I came home, and if you will allow me smelt ozone. I eventually found my power bar happily melting and smoking away. The current if you will found a ground just not the circuit ground. I Highly recommend ARC protection on any source of supply. You can do separate outlets or your entire house. Not to argue but to point out another dangerous situation.

 

[Freenow54]

Aquarium Myths and Misinformation

c. 2023 Jay Hemdal


Over the last 50 years, I’ve heard a number of myths and possible misinformation applied to aquariums and the husbandry of the animals contained in them. Most of these seem to go unchallenged; at least they keep showing up online, long after they have been shown to be incorrect.

Some of these myths take on the same characteristics as “urban legends” (Such as the story of the child who gave her hamster a bath and then used a microwave oven to dry it off – with explosive results!). These are stories that people hear and believe “that it must be true because their friend knew a person whose sister actually saw it happen”. The true source of these stories can never actually be tracked down, and most are not based in fact – although the most successful myths and legends always have a small kernel of truth to them.

I’ll admit the sticking point here is that I’m asking you to accept my de-bunking of these myths with just a little more evidence than is present in the myths themselves! I also realize that not everyone will agree with my assessment of some of these issues. I do ask those who do disagree, to reflect on why they do, some of these beliefs are so firmly entrenched in the hobby that people tend to hold them a lot more dearly than the evidence would indicate they should. At the very least I challenge you to always question unsubstantiated claims, they may turn out valid in the end, but many of them are eventually relegated to the realm of myths. Remember, it is the responsibility of the person making fantastic claims to prove their statements are correct, not the other way around. For example, you might hear somebody claim that they saw a U.F.O. If you don’t believe them, it is not your duty to prove them wrong, they must supply evidence to support their claims.

76 day fallow period (or longer) for marine ich, Cryptocaryon: Published in a paper where the co-author was also the editor for the journal. The original study was from a PhD thesis that isn’t widely available. 45 to 60 days at 81 degrees F. is a more reasonable, but still effective fallow period. Fallow periods for other disease are different.

Adding vitamins or food additives to the aquarium’s water: This just feeds the heterotrophic bacteria. Aquatic animals, if they uptake it at all, do so slower than the bacteria do.

Aquariums can hold a set number of inches of fish per gallon: You see this time and time again; “An aquarium’s holding capacity is 2” of fish per gallon”. Sometimes the number differs, in other cases the author adds refinements to the equation to take into account the aquarium’s surface area, filtration method, even water temperature. In every case, the equation has the same fatal flaw: With all else being equal, the waste output of fish, and their subsequent bio-load is not based primarily on the length of the fish, but more so their mass. An easy way to see this is to try to visualize the common formula of “two inches of fish per gallon”. Certainly, a ten gallon aquarium can safely house 20, one inch long guppies. Now, even though the “inches of fish” are equal, try adding one 20” long Pacu to the same tank and see what happens! As the length of a fish increases in a linear fashion, its mass, (and subsequent bio-load) increases by the length raised to the third power, multiplied by a constant (which varies for differently shaped fish). Another variable which also affects bio-load independent of the length of the animal is a given species innate metabolic rate; some species are more active, consume more food and thus produce more waste products than others of the same size.

Avoiding temperature shock is the main reason for acclimating fish: A variety of acclimation techniques have been presented over the years, all with the hoped-for result of reducing stress and shock to an aquarium animal being moved from one aquarium to another. Some people have embraced this idea and taken it to the extreme. There was the aquarium keeper who would float bags for fish in his tank for eight hours rather than the 30 minutes recommended by the pet store; the reasoning given was “in order to expose the fish to the slowest possible change in temperature”. Never mind that in this case, the water temperature in the bag was fully equilibrated with that of the aquarium within the first ten minutes. Even if fish were exposed to a sudden change in water temperature, just how harmful would that be? As a SCUBA diver, watching fish swimming up and down along a ten degree thermocline with apparent impunity makes me wonder. I’ve even seen a damselfish diligently guarding its nest along an 8 degree thermocline in the Galapagos Islands. The continually changing water temperature affected neither the fish nor its eggs. Overly long acclimation times do more harm than good. Take the example of fish, which have been in their bags for over 24 hours. Typically, the pH of their water will be very low, while the ammonia concentration will be high. As it turns out, ammonia is much less toxic to fish at a low pH. Imagine what happens to those fish during a lengthy acclimation; as the carbon dioxide is driven out of the shipping bags, the pH rises. Even though the aquarist is slowly adding tank water to the bag, it isn’t happening fast enough to dilute down the ammonia before the rising pH makes the ammonia toxic enough to kill the fish right in the bags. In other cases, the stress imposed on certain shy fish by restraining them in a clear bag at the surface where they cannot hide is greater than just releasing them so they can seek a secure hiding place. Acclimation times of more than 30 minutes are unnecessary and potentially do more harm than good. The only criteria that MUST be managed carefully is exposing fish to a rise in salinity/specific gravity. This must be done very slowly, or better yet, in stages, by changing the salinity of the tank itself.

Dietary supplements as a “medication”: The best diet in the world will not stop active infections – this is called the “chicken soup” syndrome. A proper diet is of course important for long-term fish health, it's just that changing to "great diet" will not stop active disease. Give this the logic test: will feeding your dog a great diet keep it from getting ticks or fleas? Of course not.

Drip acclimating shipped fish: Not if there is high ammonia. Best to match the temperature, pH and salinity and move the fish directly over and then acclimate them (with no ammonia) to your tank.

Feeding Peas to cure swim bladder issues: The recommendation of "feeding peas" has a long and convoluted history. It began as a treatment for issues with floating fancy goldfish. An aquarist at the Shedd Aquarium promoted this remedy back in the 1960’s and it does work. However, the issue with fancy goldfish is because they have weirdly shaped intestines that trap gas, making them float. Feeding peas works as a laxative, expelling the gas and allowing the fish to swim normally. At some point, this idea got "transferred" to marine fish with swim bladder problems. Feeding peas has NO benefit for swim bladder issues at all, yet the idea has been spread all over the Internet.

Fish only grow in size to fit their aquarium: Most intermediate and advanced aquarists, (or anyone who has ever purchased a Pacu) knows this statement is more accurately stated as: “Fish grow rapidly to a maximum size for that aquarium, then the growth rate slows a bit, but they still outgrow that aquarium if it is in their genetic makeup to grow that large”. Of course, the irony of this seems to be that this slowing of the growth rate only gives the aquarist time to save up money for a larger tank. When the purchase is made and the fish is placed in its spacious new quarters, its growth rate again speeds up until it again is about to outgrow its new tank!

Flying gurnards taking to the air: These bottom dwelling fish were pictured by early naturalist artists as being capable of gliding through the air like flying fish. In reality, these fish extend their huge pectoral fins in an attempt to make themselves look too large to eat by potential predators. As recently as 1976 an eminent fish taxonomist wrote that these fish are “supposedly capable of gliding short distances”. If one considers jumping out of a tank onto the floor as “gliding a short distance” then perhaps this is true, otherwise we should consider this myth dead and buried.

Flying hatchet fish: This is a rather “slippery” tale. Every once in a while, I’ll come across a reference regarding the flying ability of the South American hatchet fish. That’s right, I said FLYING not just gliding. Apparently, the argument is made that the deep breasts of these fish serve as anchor points for huge pectoral muscles, which the fish uses to vibrate its fins and achieve a sort of powered flight. One description I read told of a school of these fish taking to the air and passing by the observer’s head making a loud buzzing sound. Although these fish are well known for their ability to jump out of tanks, I’ve never seen any direct evidence of powered flight. Perhaps they need a longer runway for takeoff? I’ve toyed with the idea of adding a school of these fish to a 20,000 gallon reservoir, and then give them a scare and see if they will fly under those conditions.

Huge fish thriving in a small aquarium: From time to time, I get reports such as a three foot long snakehead living in somebody’s one foot wide by four foot long 55 gallon aquarium. As I’ve previously mentioned, the “fish growing only to a size to fit the tank” statement is a myth, as these reports seem to bear out. Either these fish have an amazing ability to survive in horrendously undersized aquariums, or people’s ability to judge the true size of their fish is impaired, or a combination of both. That recalls the story of the “Florida tape measure”. It seems that some fish dealers have in their possession a magical tape measure: nurse sharks always tape out at 14” – even if they measure 24” when you pick them up at the airport. For other species such as angelfish, the same tape measure that the collector used on the nurse shark will give them a measurement of 8” for a show-sized queen angelfish that ends up being about the size of a half dollar when you unpack it.

Iodized salt is harmful to fish: After selling non-iodized aquarium salt in pet stores for 15 years, I strongly disagreed with the person who first proposed to me that iodized table salt worked just as well as the more expensive “aquarium salt”. Everyone “knew” that the iodine would kill the fish. I had a difficult time believing that this basic tenet of freshwater aquariums was false, but it is. You can safely add the same amount of regular table salt to an aquarium as you would non-iodized aquarium salt.

Lee Chin Eng Natural system: I remember seeing the photographs of Mr. Eng’s tank in hobbyist publications in the early 1970’s and wondering why I could not re-create a similar aquarium. He was reportedly able to keep all manner of fish, corals and other invertebrates in aquariums with just a slow trickle of air. Mr. Eng has evidently passed away, so we only have his photographs to document his systems. I would urge people to study those photographs very closely; quite a bit can be deduced from them by careful observation: A lot of the photos show huge numbers of shrimpfish along with damselfish, clownfish and batfish. Anyone who has successfully kept shrimpfish knows that they do best if fed live mysid shrimp and cannot compete against other fish for live food. My strong opinion is that Mr. Eng added these shrimpfish a short time before taking the photo – and may have done the same with some of the more delicate invertebrates in the tank. Other pictures show corals placed in unnatural positions, showing no evidence of any in-situ growth. Many of the other organisms are hardy species (at least for the short term) such as feather dusters, carpet anemones and red starfish. My hunch is that Mr. Eng set up aquariums with live rock and hardy animals, and then just prior to being photographed, he “spruced the tanks up” by adding a few showy, but delicate species.

Mangrove seedlings help maintain marine aquarium water quality: I can’t recall how many dead and dying mangrove seedlings I’ve recently seen offered for sale, floating jammed into pieces of Styrofoam in dealer’s holding tanks. Keeping mangroves healthy in aquariums is not a simple matter; they are prone to developing scale insect diseases and require very high light levels. Even if the plants do thrive, the argument that they will actively remove organic waste products from the aquarium’s water is difficult to prove. In one case, a 200-gallon exhibit containing three large, actively growing mangrove trees had been set up for two years. It did have a fairly heavy bio-load of fish, but an orthophosphate reading of 7.5 mg/l was totally unexpected based on the supposed nutrient removal ability of mangroves.

Mixing medications with focus + food: This cannot work unless you calculate the dose properly. General Cure should not be dosed orally, as the two components have two different oral doses. This article discusses that: https://www.reef2reef.com/ams/proper-dosing-of-medicated-foods.780/

Mortality caused by medications, years after application: Copper, formalin and cyanide have all been implicated in fish loss years after exposure – this is not borne out by histopathology or veterinary necropsy. Public aquariums all have comprehensive, proactive quarantine/treatment protocols, yet they have some of the longest-lived fish. I've done three studies since 1983 that all show that latent cyanide mortality (while often severe) always manifests itself within 30 to 50 days of exposure. Long term copper exposure has been shown to cause damage to fish, but this is ionic, not chelated copper, and the toxicity appeared during or shortly after the copper exposure.

Nitrite is toxic to marine fish: Ammonia is highly toxic to marine fish at a high pH, but the salts in the water completely de-toxify nitrite ions for marine fish. Nitrite IS deadly to freshwater fish, unless some salt is added to the water.

Predatory fish, which will only accept live foods: I remember in the 1970’s, thinking that lionfish would only eat living fish. Sure enough, all my lionfish would greedily accept “feeder fish” from the very start and would always steadfastly refuse anything else once they have become accustomed to that diet! This was really just a case of a self-fulfilling prophecy, I expected them to eat only goldfish and sure enough, that’s what they became accustomed to! There are a variety of reasons why non-living foods may be preferable; lower cost, ease of storage, ability to supplement with vitamins, etc. Can every species of fish be “trained” to feed on non-living food? It seems that almost any species can, if the required amount of effort is made. The basic trick seems to be to begin feeding the fish an acceptable living food, but very soon after, begin inter-mixing some freshly killed individuals of the same food. As soon as possible, switch the animal over to all dead food, then begin offering slivers of the prepared food made the same size and shape as the accepted prey item. This technique works very well for anglerfish, lionfish and even trumpetfish. In some cases, though, the training effort is simply too great (such as with shrimpfish, seadragons and leaf fish). I once had a report that a person had gotten their seahorse to feed on flake food using this method, but I never saw this firsthand, and would hate to create another myth by putting too much stock in that story!

Ramp up medications slowly: Too many fish die from disease if you take too long, dealers don’t do this, should you? (the only exception is salt when you are raising the salinity or the old ionic copper/citric acid solutions).

Red-rimmed batfish feeding on bananas: Years ago, a person wrote an article for his local aquarium club recalling his experience feeding bananas to a pair of red-rimmed batfish (Platax pinnatus). His argument was that since batfish are residents of mangrove swamps, they should be well adapted to feeding on plant material. By that same train of thought, lions should be well adapted for feeding on grass because they are found in the grasslands of Africa. In addition, the red-rimmed batfish is a resident of deeper coral reefs; it is the round batfish, (Platax orbicularis) which is found as juveniles in mangrove areas. I’ll admit, I have tried feeding bananas to red-rimmed batfish on three occasions (but have never gotten one to accept any). As the article goes on, the author reports that the fish grew to a height which was 2” taller than the aquarium he reported keeping them in – it’s possible that the entire article was some sort of practical joke. The danger is that this article still gets referred to once in a while, it is archived in an on-line computer database, and people keep finding it when they run a search for information about this species.

Small aquariums are inherently less stable than larger ones: I love this myth! It’s one that every aquarist “knows is true” and has been around since long before the advent of thermostatically controlled heaters but should have been dropped once those devices were developed. You see, the only parameter, which is more variable in smaller aquariums than larger ones, is the effect that ambient air temperature has on unheated water. Small tanks will cool down quicker and heat up faster than larger tanks. Once thermostatic heaters were invented, this simply didn’t matter anymore. Take the case where you have two aquariums, and the only variable is their size – they have comparable filtration and other life support equipment (appropriately sized for each tank). If you then compare a ten gallon aquarium, which is housing “X” grams of biomass per gallon and 100 gallon aquarium housing the same ratio of biomass to volume, the biological stability of the two systems will be identical. This myth got its start in unheated tanks, but two other underlying problems have fueled it over the years. Notice that I said that the two tanks need to have comparable life support equipment. Very often, smaller aquariums have cheaply made filters and heaters, which negatively affect the overall stability of the system. In addition, it is much, much easier to overcrowd a smaller aquarium than it is a larger one; adding an extra 2” long swordtail to an already over-crowded ten gallon aquarium might increase the total bio-load of the system by 20%. The same fish being added to a similarly crowded 100 gallon aquarium would increase the total bio-load by perhaps 2%. The relative instability of these smaller tanks can often be documented, but the root of the problem is not directly correlated with the size of the tank.

Snapping shrimp can break aquarium glass when they snap their claws: I first heard this when I was about 12, when I purchased a small snapping shrimp and was warned by the salesperson that they “have been known to crack the glass of tanks”. After adding the shrimp to a small aquarium in my bedroom, I had a rough couple of nights, jumping up to check the tank every time I heard a snap. The glass never broke, nor have I heard any firsthand accounts of this phenomenon (it’s always, “It happened to a friend of mine’s brother). There are reports of snapping shrimp stunning fish which swim by, so there is apparently some force behind their “pop”, just not enough to crack glass.

“Stray voltage” causes fish loss or health issues: This is a red herring, stray or induced voltage (typically < 50 VAC) has no measurable effect on aquarium fish, as they are not grounded, so there is no electrical potential. Stray voltage has been ruled out as a cause of HLLE. True electrical shorts can harm or kill fish, as well as people. All aquariums must be plugged into GFI circuits.

Tank Transfer Method (TTM): This method does work, but in my opinion, it works best for ich (Cryptocaryon) and not for egg laying flukes at all. It can be very rough on fish due to ammonia and excessive handling, and already stressed fish being housed in buckets. Remember that lateral viewing of new fish is a vital tool for diagnosis. Top down views in buckets or totes do not give you a good enough view of how the fish is doing. Then, just when is TTM useful given the logistics of treating diseases? If you use it as part of a quarantine process, you still need a single tank to run the fish through additional quarantine for flukes. If your DT develops ich and you want to use TTM, you can't do that and just put the fish back into the DT, the ich will still be active. That means you would run TTM, but then need to move the fish to another tank during the proper fallow period for the main display aquarium.

Ultraviolet Sterilizers eliminate diseases from aquarium water: Ultraviolet units have absolutely no effect on disease organisms, which live on the fish directly and do not need to leave the fish during some part of its life cycle (some protozoans, trematodes and most pathogenic bacteria). Other parasites such as larger protozoans and all multicellular parasites too big to be killed by aquarium-sized UV units. The expected benefits from a properly operating UV sterilizer would be a lowering of the free-floating bacterial and protozoan populations, as well as fairly good control (close to 100%) of these organisms when water flowing from one tank to another first passes through the UV sterilizer. Side-stream sterilization, where the irradiated water is returned to the same tank is was taken from is always less than 100% effective – too many of the target organisms are able to escape passing through the unit and are able to continue to reproduce.

Using RODI and no aeration for FW dips: Use aerated, pH and temperature balanced water in all cases. Tap water is fine!

Using black mollies as “canaries in a coal mine”: Really only screens for ich, Cryptocaryon, and can introduce euryhaline (brackish water) trematodes into the system, as well as internal parasites carried by the non-quarantined mollies.

###

Should this be on your List? API bashing inaccurate True or False?

 

[ReefGeezer]

Hi Jay. Great post. Can you speak to the theory that fish can develop "immunity" to, or somehow survive in closed systems where ich/velvet are present. I have always thought that water/environment quality and stability could possible make for better health and help fish resist parasites longer, and I suspect that some corals and other organisms might help control some parasites in the free swimming state, but I just don't understand the mechanism(s) that might make a fish "immune" to these parasites. Thanks.

 

[Jay Hemdal]

Hi Jay. Great post. Can you speak to the theory that fish can develop "immunity" to, or somehow survive in closed systems where ich/velvet are present. I have always thought that water/environment quality and stability could possible make for better health and help fish resist parasites longer, and I suspect that some corals and other organisms might help control some parasites in the free swimming state, but I just don't understand the mechanism(s) that might make a fish "immune" to these parasites. Thanks.

There is acquired immunity for some fish parasites, but it is temporary, and not 100%. It has been documented in ich and in Neobenedenia flukes.

Here is some text that I wrote up on this:

Immunity in Fish - The ability for a fish to fight off a disease (or not) is based on the level of immunity it has. A physically stressed fish will have a lower immunity level and be more prone to developing disease. However, people tend to rely too much on immunity and they think that if they offer the fish a great diet, it will be (mostly) free of disease. Some people extrapolate that even further and think that if they have a sick fish, if they feed it well, they can cure it (the chicken soup syndrome). The reality is that fish have a less developed immune response than mammals do, and we know that with humans, even the best diet and exercise does not prevent all diseases and in some instances really doesn’t help much at all. Immunity varies between the parasite involved. Bacterial diseases are rarely communicable because the fish have good defense (skin structure) and good immunity against them.

Innate immunity – this is the fish’s genetic predisposition to being able to fight off infections using its normal antibody system. There are differences seen between species of fish, with the example of Achilles tangs being much more prone to developing Cryptocaryon infections than are yellow tangs. Innate immunity is the baseline level, the starting point and nothing really changes that in a given individual.

Immunity conferred by good diet/environment – Fish with lower stress levels will have better immunity. Keeping the fish in a stable aquarium, with no aggressive tankmates, good water quality and a great diet will help boost its immunity. However, people often fail to understand that the disease organism themselves can be a major stressor, and can override all immunity conferred by a good environment.

Acquired immunity – This type of immunity is mounted by a fish after exposure to (and survival from) some disease outbreak. Antibodies are created that help the fish fight off future infections from that disease organism. Too many times in aquariums, the fish does not survive the disease challenge, so no acquired immunity is possible. In most cases, the only functional benefit for this is seen with sub-lethal viral diseases such as Lymphocystis; a fish that recovers from that disease rarely acquires it again. Wild fish have very little acquired immunity by virtue of not being infected with disease organisms to a high enough degree (or if they are, they get eaten by predators due to their weakened state). Immune responses in fish seems strongest against viruses and least against multi-celled parasites such as flukes. Parasites living on the skin or gills of fish are less exposed to the antibodies, so acquired immunity to protozoans and metazoans such as Cryptocaryon, Amyloodinium and flukes is only partial and transient.

Jay

 

[Jay Hemdal]

Should this be on your List? API bashing inaccurate True or False?

I try not to speak ill of commercial products, safer that way (grin).

Jay

 

[Jay Hemdal]

As to stray voltage. I totally agree with your statement of the fish not being grounded which is necessary to turn anything into a " load "to kill it However have you ever been part of a circuit and not grounded? You can certainly feel the potential in your body. I have learned for an absolute fact that a simple GFI outlet even with a bar with surge protection is simply not enough to prevent house fires. A GFI simply measures Amperage in and returning and opens the circuit with a very small difference which I forget. All of the numbers along with how much amperage it takes to kill a human are available . I will happily provide facts if anyone wants . It is way less than an amp. I experienced another truth for myself. I came home, and if you will allow me smelt ozone. I eventually found my power bar happily melting and smoking away. The current if you will found a ground just not the circuit ground. I Highly recommend ARC protection on any source of supply. You can do separate outlets or your entire house. Not to argue but to point out another dangerous situation.

Stray voltage is a bit of a misnomer, should be called induced voltage, often from AC motors in the aquarium. That has been implicated in all sorts of fish health issues, but has never been actually proven to cause any issues at all.

Jay

 

[Jay Hemdal]

@Jay Hemdal can you please elaborate a bit more on the use of UV? Did I understand correctly that it does nothing for the free floating stages of Ick and Velvet? I mainly use UV to try and mitigate potential disease outbreaks...

Thanks!

A properly sized UV (usually larger than most hobbyist units) can kill free floating ich or velvet theronts/tomites. However, UV will do nothing for disease organisms on the fish itself. Also, "dwell time" comes into play - lets say the UV unit is on a 30% side stream and it is capable of killing 90% of the tomites in one pass. the trouble is that in severe infections, new tomites are formed faster than they can be killed by the UV and the infection continues.

Jay

 

[ErikVR]

Fish only grow in size to fit their aquarium

I've read articles explaining that a fish's growth is stunted by having a tank that's too small, causing its organs to develop improperly. Leading to an unhealthy fish that won't live long. Never known for a fact that this is true though.

 

[brandon429]

the end all/be all/final answer to api ammonia bashing is this: anyone who wants to know, get a seneye and set it up, calibrate it and take the readings from your running display tank to prove it's within spec. then use that same slide and make cycling tests and run api alongside it. the seneye will be the correct one, let us know of the posted results. if you can get the api to agree with the seneye, in the same time frame of resolve rates, then six million posts on api have been wrong

someone's subjective statements on API don't matter in the beef, everyone knows Taricha has no problem with one. bench it against a calibrated seneye and post them results for the objective win to the matter. res publica does not wield that test well, that's a fact. Taricha and Dan sure do, that's a fact.

 

[ReefGeezer]

There is acquired immunity for some fish parasites, but it is temporary, and not 100%. It has been documented in ich and in Neobenedenia flukes.

Here is some text that I wrote up on this:

Immunity in Fish - The ability for a fish to fight off a disease (or not) is based on the level of immunity it has. A physically stressed fish will have a lower immunity level and be more prone to developing disease. However, people tend to rely too much on immunity and they think that if they offer the fish a great diet, it will be (mostly) free of disease. Some people extrapolate that even further and think that if they have a sick fish, if they feed it well, they can cure it (the chicken soup syndrome). The reality is that fish have a less developed immune response than mammals do, and we know that with humans, even the best diet and exercise does not prevent all diseases and in some instances really doesn’t help much at all. Immunity varies between the parasite involved. Bacterial diseases are rarely communicable because the fish have good defense (skin structure) and good immunity against them.

Innate immunity – this is the fish’s genetic predisposition to being able to fight off infections using its normal antibody system. There are differences seen between species of fish, with the example of Achilles tangs being much more prone to developing Cryptocaryon infections than are yellow tangs. Innate immunity is the baseline level, the starting point and nothing really changes that in a given individual.

Immunity conferred by good diet/environment – Fish with lower stress levels will have better immunity. Keeping the fish in a stable aquarium, with no aggressive tankmates, good water quality and a great diet will help boost its immunity. However, people often fail to understand that the disease organism themselves can be a major stressor, and can override all immunity conferred by a good environment.

Acquired immunity – This type of immunity is mounted by a fish after exposure to (and survival from) some disease outbreak. Antibodies are created that help the fish fight off future infections from that disease organism. Too many times in aquariums, the fish does not survive the disease challenge, so no acquired immunity is possible. In most cases, the only functional benefit for this is seen with sub-lethal viral diseases such as Lymphocystis; a fish that recovers from that disease rarely acquires it again. Wild fish have very little acquired immunity by virtue of not being infected with disease organisms to a high enough degree (or if they are, they get eaten by predators due to their weakened state). Immune responses in fish seems strongest against viruses and least against multi-celled parasites such as flukes. Parasites living on the skin or gills of fish are less exposed to the antibodies, so acquired immunity to protozoans and metazoans such as Cryptocaryon, Amyloodinium and flukes is only partial and transient.

Jay

Thanks Jay. Again, this is a great thread.

 

[Costareefer]

A properly sized UV (usually larger than most hobbyist units) can kill free floating ich or velvet theronts/tomites. However, UV will do nothing for disease organisms on the fish itself. Also, "dwell time" comes into play - lets say the UV unit is on a 30% side stream and it is capable of killing 90% of the tomites in one pass. the trouble is that in severe infections, new tomites are formed faster than they can be killed by the UV and the infection continues.

Jay

UV (undersized) is a practice that acts as an inoculation for fish ime. I’ve been studying this for 20 years and while I am an amateur marine biologist (been diving 30 years keeping reef tanks for 25+) I think I have enough evidence that UV reduces the numbers of free swimming parasites leading to fish having the ability to build up its immune system and keeping outbreaks at bay. Think about all the masking during COVID. As soon as the masks came off everyone started getting serious sickness from the common cold and other pathogens our immune system had been shielded from. Our reef tanks are not the open ocean where parasitic numbers are far less concentrated than an outbreak in our tank. I’ve had a lot of experience with direct from to sea to tank captivity of fish and other organisms.

Also I know what your research says about GC but imo it does work when fed even in the display. I used to qt but no longer do I mean I think qting to avoid fish illness is misinfo. Too many reefers have qtd and still had massive breakouts. Or worse their fish die in qt bc it is not a natural environment and causes a great deal of stress on fish. QTing for a fallow tank ime is misinformation.

Finally the urban legend I want to know about is the story about the dudes dog that died after drinking seawater in a bucket containing palys. I know they can kill but my dog doesn’t touch saltwater and while it’s plausible it always sounded like a far fetched story.

 

[livinlifeinBKK]

Ive always been skeptical of garlic...I don't remember precisely where I read about how it got popular a while back but it was written by a credible source and it was tried to entice fish to eat at an aquarium if I remember correctly. Something along the lines of 1/5 of the fish that were sick and refusing to take food finally ate after being fed garlic. If my memory is even remotely close, it was actually a failure a marketing company put a spin on but when you put a product in a nice package it must work, right? I'll try to find where I read it and post it for you guys

 

[wjm6449]

Aquarium Myths and Misinformation

c. 2023 Jay Hemdal


Over the last 50 years, I’ve heard a number of myths and possible misinformation applied to aquariums and the husbandry of the animals contained in them. Most of these seem to go unchallenged; at least they keep showing up online, long after they have been shown to be incorrect.

Some of these myths take on the same characteristics as “urban legends” (Such as the story of the child who gave her hamster a bath and then used a microwave oven to dry it off – with explosive results!). These are stories that people hear and believe “that it must be true because their friend knew a person whose sister actually saw it happen”. The true source of these stories can never actually be tracked down, and most are not based in fact – although the most successful myths and legends always have a small kernel of truth to them.

I’ll admit the sticking point here is that I’m asking you to accept my de-bunking of these myths with just a little more evidence than is present in the myths themselves! I also realize that not everyone will agree with my assessment of some of these issues. I do ask those who do disagree, to reflect on why they do, some of these beliefs are so firmly entrenched in the hobby that people tend to hold them a lot more dearly than the evidence would indicate they should. At the very least I challenge you to always question unsubstantiated claims, they may turn out valid in the end, but many of them are eventually relegated to the realm of myths. Remember, it is the responsibility of the person making fantastic claims to prove their statements are correct, not the other way around. For example, you might hear somebody claim that they saw a U.F.O. If you don’t believe them, it is not your duty to prove them wrong, they must supply evidence to support their claims.

76 day fallow period (or longer) for marine ich, Cryptocaryon: Published in a paper where the co-author was also the editor for the journal. The original study was from a PhD thesis that isn’t widely available. 45 to 60 days at 81 degrees F. is a more reasonable, but still effective fallow period. Fallow periods for other disease are different.

Adding vitamins or food additives to the aquarium’s water: This just feeds the heterotrophic bacteria. Aquatic animals, if they uptake it at all, do so slower than the bacteria do.

Aquariums can hold a set number of inches of fish per gallon: You see this time and time again; “An aquarium’s holding capacity is 2” of fish per gallon”. Sometimes the number differs, in other cases the author adds refinements to the equation to take into account the aquarium’s surface area, filtration method, even water temperature. In every case, the equation has the same fatal flaw: With all else being equal, the waste output of fish, and their subsequent bio-load is not based primarily on the length of the fish, but more so their mass. An easy way to see this is to try to visualize the common formula of “two inches of fish per gallon”. Certainly, a ten gallon aquarium can safely house 20, one inch long guppies. Now, even though the “inches of fish” are equal, try adding one 20” long Pacu to the same tank and see what happens! As the length of a fish increases in a linear fashion, its mass, (and subsequent bio-load) increases by the length raised to the third power, multiplied by a constant (which varies for differently shaped fish). Another variable which also affects bio-load independent of the length of the animal is a given species innate metabolic rate; some species are more active, consume more food and thus produce more waste products than others of the same size.

Avoiding temperature shock is the main reason for acclimating fish: A variety of acclimation techniques have been presented over the years, all with the hoped-for result of reducing stress and shock to an aquarium animal being moved from one aquarium to another. Some people have embraced this idea and taken it to the extreme. There was the aquarium keeper who would float bags for fish in his tank for eight hours rather than the 30 minutes recommended by the pet store; the reasoning given was “in order to expose the fish to the slowest possible change in temperature”. Never mind that in this case, the water temperature in the bag was fully equilibrated with that of the aquarium within the first ten minutes. Even if fish were exposed to a sudden change in water temperature, just how harmful would that be? As a SCUBA diver, watching fish swimming up and down along a ten degree thermocline with apparent impunity makes me wonder. I’ve even seen a damselfish diligently guarding its nest along an 8 degree thermocline in the Galapagos Islands. The continually changing water temperature affected neither the fish nor its eggs. Overly long acclimation times do more harm than good. Take the example of fish, which have been in their bags for over 24 hours. Typically, the pH of their water will be very low, while the ammonia concentration will be high. As it turns out, ammonia is much less toxic to fish at a low pH. Imagine what happens to those fish during a lengthy acclimation; as the carbon dioxide is driven out of the shipping bags, the pH rises. Even though the aquarist is slowly adding tank water to the bag, it isn’t happening fast enough to dilute down the ammonia before the rising pH makes the ammonia toxic enough to kill the fish right in the bags. In other cases, the stress imposed on certain shy fish by restraining them in a clear bag at the surface where they cannot hide is greater than just releasing them so they can seek a secure hiding place. Acclimation times of more than 30 minutes are unnecessary and potentially do more harm than good. The only criteria that MUST be managed carefully is exposing fish to a rise in salinity/specific gravity. This must be done very slowly, or better yet, in stages, by changing the salinity of the tank itself.

Dietary supplements as a “medication”: The best diet in the world will not stop active infections – this is called the “chicken soup” syndrome. A proper diet is of course important for long-term fish health, it's just that changing to "great diet" will not stop active disease. Give this the logic test: will feeding your dog a great diet keep it from getting ticks or fleas? Of course not.

Drip acclimating shipped fish: Not if there is high ammonia. Best to match the temperature, pH and salinity and move the fish directly over and then acclimate them (with no ammonia) to your tank.

Feeding Peas to cure swim bladder issues: The recommendation of "feeding peas" has a long and convoluted history. It began as a treatment for issues with floating fancy goldfish. An aquarist at the Shedd Aquarium promoted this remedy back in the 1960’s and it does work. However, the issue with fancy goldfish is because they have weirdly shaped intestines that trap gas, making them float. Feeding peas works as a laxative, expelling the gas and allowing the fish to swim normally. At some point, this idea got "transferred" to marine fish with swim bladder problems. Feeding peas has NO benefit for swim bladder issues at all, yet the idea has been spread all over the Internet.

Fish only grow in size to fit their aquarium: Most intermediate and advanced aquarists, (or anyone who has ever purchased a Pacu) knows this statement is more accurately stated as: “Fish grow rapidly to a maximum size for that aquarium, then the growth rate slows a bit, but they still outgrow that aquarium if it is in their genetic makeup to grow that large”. Of course, the irony of this seems to be that this slowing of the growth rate only gives the aquarist time to save up money for a larger tank. When the purchase is made and the fish is placed in its spacious new quarters, its growth rate again speeds up until it again is about to outgrow its new tank!

Flying gurnards taking to the air: These bottom dwelling fish were pictured by early naturalist artists as being capable of gliding through the air like flying fish. In reality, these fish extend their huge pectoral fins in an attempt to make themselves look too large to eat by potential predators. As recently as 1976 an eminent fish taxonomist wrote that these fish are “supposedly capable of gliding short distances”. If one considers jumping out of a tank onto the floor as “gliding a short distance” then perhaps this is true, otherwise we should consider this myth dead and buried.

Flying hatchet fish: This is a rather “slippery” tale. Every once in a while, I’ll come across a reference regarding the flying ability of the South American hatchet fish. That’s right, I said FLYING not just gliding. Apparently, the argument is made that the deep breasts of these fish serve as anchor points for huge pectoral muscles, which the fish uses to vibrate its fins and achieve a sort of powered flight. One description I read told of a school of these fish taking to the air and passing by the observer’s head making a loud buzzing sound. Although these fish are well known for their ability to jump out of tanks, I’ve never seen any direct evidence of powered flight. Perhaps they need a longer runway for takeoff? I’ve toyed with the idea of adding a school of these fish to a 20,000 gallon reservoir, and then give them a scare and see if they will fly under those conditions.

Huge fish thriving in a small aquarium: From time to time, I get reports such as a three foot long snakehead living in somebody’s one foot wide by four foot long 55 gallon aquarium. As I’ve previously mentioned, the “fish growing only to a size to fit the tank” statement is a myth, as these reports seem to bear out. Either these fish have an amazing ability to survive in horrendously undersized aquariums, or people’s ability to judge the true size of their fish is impaired, or a combination of both. That recalls the story of the “Florida tape measure”. It seems that some fish dealers have in their possession a magical tape measure: nurse sharks always tape out at 14” – even if they measure 24” when you pick them up at the airport. For other species such as angelfish, the same tape measure that the collector used on the nurse shark will give them a measurement of 8” for a show-sized queen angelfish that ends up being about the size of a half dollar when you unpack it.

Iodized salt is harmful to fish: After selling non-iodized aquarium salt in pet stores for 15 years, I strongly disagreed with the person who first proposed to me that iodized table salt worked just as well as the more expensive “aquarium salt”. Everyone “knew” that the iodine would kill the fish. I had a difficult time believing that this basic tenet of freshwater aquariums was false, but it is. You can safely add the same amount of regular table salt to an aquarium as you would non-iodized aquarium salt.

Lee Chin Eng Natural system: I remember seeing the photographs of Mr. Eng’s tank in hobbyist publications in the early 1970’s and wondering why I could not re-create a similar aquarium. He was reportedly able to keep all manner of fish, corals and other invertebrates in aquariums with just a slow trickle of air. Mr. Eng has evidently passed away, so we only have his photographs to document his systems. I would urge people to study those photographs very closely; quite a bit can be deduced from them by careful observation: A lot of the photos show huge numbers of shrimpfish along with damselfish, clownfish and batfish. Anyone who has successfully kept shrimpfish knows that they do best if fed live mysid shrimp and cannot compete against other fish for live food. My strong opinion is that Mr. Eng added these shrimpfish a short time before taking the photo – and may have done the same with some of the more delicate invertebrates in the tank. Other pictures show corals placed in unnatural positions, showing no evidence of any in-situ growth. Many of the other organisms are hardy species (at least for the short term) such as feather dusters, carpet anemones and red starfish. My hunch is that Mr. Eng set up aquariums with live rock and hardy animals, and then just prior to being photographed, he “spruced the tanks up” by adding a few showy, but delicate species.

Mangrove seedlings help maintain marine aquarium water quality: I can’t recall how many dead and dying mangrove seedlings I’ve recently seen offered for sale, floating jammed into pieces of Styrofoam in dealer’s holding tanks. Keeping mangroves healthy in aquariums is not a simple matter; they are prone to developing scale insect diseases and require very high light levels. Even if the plants do thrive, the argument that they will actively remove organic waste products from the aquarium’s water is difficult to prove. In one case, a 200-gallon exhibit containing three large, actively growing mangrove trees had been set up for two years. It did have a fairly heavy bio-load of fish, but an orthophosphate reading of 7.5 mg/l was totally unexpected based on the supposed nutrient removal ability of mangroves.

Mixing medications with focus + food: This cannot work unless you calculate the dose properly. General Cure should not be dosed orally, as the two components have two different oral doses. This article discusses that: https://www.reef2reef.com/ams/proper-dosing-of-medicated-foods.780/

Mortality caused by medications, years after application: Copper, formalin and cyanide have all been implicated in fish loss years after exposure – this is not borne out by histopathology or veterinary necropsy. Public aquariums all have comprehensive, proactive quarantine/treatment protocols, yet they have some of the longest-lived fish. I've done three studies since 1983 that all show that latent cyanide mortality (while often severe) always manifests itself within 30 to 50 days of exposure. Long term copper exposure has been shown to cause damage to fish, but this is ionic, not chelated copper, and the toxicity appeared during or shortly after the copper exposure.

Nitrite is toxic to marine fish: Ammonia is highly toxic to marine fish at a high pH, but the salts in the water completely de-toxify nitrite ions for marine fish. Nitrite IS deadly to freshwater fish, unless some salt is added to the water.

Predatory fish, which will only accept live foods: I remember in the 1970’s, thinking that lionfish would only eat living fish. Sure enough, all my lionfish would greedily accept “feeder fish” from the very start and would always steadfastly refuse anything else once they have become accustomed to that diet! This was really just a case of a self-fulfilling prophecy, I expected them to eat only goldfish and sure enough, that’s what they became accustomed to! There are a variety of reasons why non-living foods may be preferable; lower cost, ease of storage, ability to supplement with vitamins, etc. Can every species of fish be “trained” to feed on non-living food? It seems that almost any species can, if the required amount of effort is made. The basic trick seems to be to begin feeding the fish an acceptable living food, but very soon after, begin inter-mixing some freshly killed individuals of the same food. As soon as possible, switch the animal over to all dead food, then begin offering slivers of the prepared food made the same size and shape as the accepted prey item. This technique works very well for anglerfish, lionfish and even trumpetfish. In some cases, though, the training effort is simply too great (such as with shrimpfish, seadragons and leaf fish). I once had a report that a person had gotten their seahorse to feed on flake food using this method, but I never saw this firsthand, and would hate to create another myth by putting too much stock in that story!

Ramp up medications slowly: Too many fish die from disease if you take too long, dealers don’t do this, should you? (the only exception is salt when you are raising the salinity or the old ionic copper/citric acid solutions).

Red-rimmed batfish feeding on bananas: Years ago, a person wrote an article for his local aquarium club recalling his experience feeding bananas to a pair of red-rimmed batfish (Platax pinnatus). His argument was that since batfish are residents of mangrove swamps, they should be well adapted to feeding on plant material. By that same train of thought, lions should be well adapted for feeding on grass because they are found in the grasslands of Africa. In addition, the red-rimmed batfish is a resident of deeper coral reefs; it is the round batfish, (Platax orbicularis) which is found as juveniles in mangrove areas. I’ll admit, I have tried feeding bananas to red-rimmed batfish on three occasions (but have never gotten one to accept any). As the article goes on, the author reports that the fish grew to a height which was 2” taller than the aquarium he reported keeping them in – it’s possible that the entire article was some sort of practical joke. The danger is that this article still gets referred to once in a while, it is archived in an on-line computer database, and people keep finding it when they run a search for information about this species.

Small aquariums are inherently less stable than larger ones: I love this myth! It’s one that every aquarist “knows is true” and has been around since long before the advent of thermostatically controlled heaters but should have been dropped once those devices were developed. You see, the only parameter, which is more variable in smaller aquariums than larger ones, is the effect that ambient air temperature has on unheated water. Small tanks will cool down quicker and heat up faster than larger tanks. Once thermostatic heaters were invented, this simply didn’t matter anymore. Take the case where you have two aquariums, and the only variable is their size – they have comparable filtration and other life support equipment (appropriately sized for each tank). If you then compare a ten gallon aquarium, which is housing “X” grams of biomass per gallon and 100 gallon aquarium housing the same ratio of biomass to volume, the biological stability of the two systems will be identical. This myth got its start in unheated tanks, but two other underlying problems have fueled it over the years. Notice that I said that the two tanks need to have comparable life support equipment. Very often, smaller aquariums have cheaply made filters and heaters, which negatively affect the overall stability of the system. In addition, it is much, much easier to overcrowd a smaller aquarium than it is a larger one; adding an extra 2” long swordtail to an already over-crowded ten gallon aquarium might increase the total bio-load of the system by 20%. The same fish being added to a similarly crowded 100 gallon aquarium would increase the total bio-load by perhaps 2%. The relative instability of these smaller tanks can often be documented, but the root of the problem is not directly correlated with the size of the tank.

Snapping shrimp can break aquarium glass when they snap their claws: I first heard this when I was about 12, when I purchased a small snapping shrimp and was warned by the salesperson that they “have been known to crack the glass of tanks”. After adding the shrimp to a small aquarium in my bedroom, I had a rough couple of nights, jumping up to check the tank every time I heard a snap. The glass never broke, nor have I heard any firsthand accounts of this phenomenon (it’s always, “It happened to a friend of mine’s brother). There are reports of snapping shrimp stunning fish which swim by, so there is apparently some force behind their “pop”, just not enough to crack glass.

“Stray voltage” causes fish loss or health issues: This is a red herring, stray or induced voltage (typically < 50 VAC) has no measurable effect on aquarium fish, as they are not grounded, so there is no electrical potential. Stray voltage has been ruled out as a cause of HLLE. True electrical shorts can harm or kill fish, as well as people. All aquariums must be plugged into GFI circuits.

Tank Transfer Method (TTM): This method does work, but in my opinion, it works best for ich (Cryptocaryon) and not for egg laying flukes at all. It can be very rough on fish due to ammonia and excessive handling, and already stressed fish being housed in buckets. Remember that lateral viewing of new fish is a vital tool for diagnosis. Top down views in buckets or totes do not give you a good enough view of how the fish is doing. Then, just when is TTM useful given the logistics of treating diseases? If you use it as part of a quarantine process, you still need a single tank to run the fish through additional quarantine for flukes. If your DT develops ich and you want to use TTM, you can't do that and just put the fish back into the DT, the ich will still be active. That means you would run TTM, but then need to move the fish to another tank during the proper fallow period for the main display aquarium.

Ultraviolet Sterilizers eliminate diseases from aquarium water: Ultraviolet units have absolutely no effect on disease organisms, which live on the fish directly and do not need to leave the fish during some part of its life cycle (some protozoans, trematodes and most pathogenic bacteria). Other parasites such as larger protozoans and all multicellular parasites too big to be killed by aquarium-sized UV units. The expected benefits from a properly operating UV sterilizer would be a lowering of the free-floating bacterial and protozoan populations, as well as fairly good control (close to 100%) of these organisms when water flowing from one tank to another first passes through the UV sterilizer. Side-stream sterilization, where the irradiated water is returned to the same tank is was taken from is always less than 100% effective – too many of the target organisms are able to escape passing through the unit and are able to continue to reproduce.

Using RODI and no aeration for FW dips: Use aerated, pH and temperature balanced water in all cases. Tap water is fine!

Using black mollies as “canaries in a coal mine”: Really only screens for ich, Cryptocaryon, and can introduce euryhaline (brackish water) trematodes into the system, as well as internal parasites carried by the non-quarantined mollies.

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Great article. However hold up, you’re saying table salt can actually be used?

 

[livinlifeinBKK]

Great article. However hold up, you’re saying table salt can actually be used?

I think his point was that people believed that it would be deadly since it was iodized but didn't have any reason to believe that aside from hearing someone else say it would be deadly. Table salt and aquarium salt aren't close to identical in composition of trace elements.

 

[wjm6449]

I think his point was that people believed that it would be deadly since it was iodized but didn't have any reason to believe that aside from hearing someone else say it would be deadly. Table salt and aquarium salt aren't close to identical in composition of trace elements.

I see. It would be fascinating for someone to do a trial and error run with table salt minus coral and with some basic fish but obviously it could result in some animal cruelty. Would regardless be interesting

 

[livinlifeinBKK]

I see. It would be fascinating for someone to do a trial and error run with table salt minus coral and with some basic fish but obviously it could result in some animal cruelty. Would regardless be interesting

These are literally my favorite threads because a personal pet peeve of mine is when people present something as if it were an empirical fact when in actuality they have no idea if what they're saying has a shred of truth to it.

 

[bluemon]

Great article. However hold up, you’re saying table salt can actually be used?

My question is, isn't table salt more expensive pound for pound?

Other than in emergencies, why would anyone use table salt?

 

[Jay Hemdal]

Great article. However hold up, you’re saying table salt can actually be used?

Not in marine tanks(grin). Freshwater aquarists are sold special “aquarium salt” to use as a tonic, but you can just substitute table salt for that…..
Jay

 

[bushdoc]

"Aquariums can hold a set number of inches of fish per gallon"
I grew up in this era and perhaps decade ago realized that it is not exactly as it says, because of variability of fish shapes and othe factors, like amount of live rock and other filtration methods.
Unfortunately I see many cries for help on this forum, when clearly amount of fish per gal of aquarium water is grossly exceeded, causing stress, diseases, hypoxia etc. We do need some simple rule of thumb for new adepts of this hobby, so nobody puts tangs in 30 gal tank.