What is a healthy fish?

[foxt]

If we can have easier access to living marine foods, this hobby will be far easier for many people.

An easy way to acquire, cultivate, and feed a variety of live foods would be perhaps the single biggest positive development in the hobby since, I dunno, salt mixes?

In some cases, we are already there. It is "easy" to sustain a population of copepods, and they automatically feed my tank (not Apex or Profilux required!). My clownfish treat my tank to fresh-hatched fry on a regular basis, so I put that in the "easy" category. It is somewhat easy to hatch and feed baby brine (PaulB feeder, anyone?). Not as easy, but very doable, to culture phyto and blackworms, although I still need to move them from the culture to the tank. Not so easy with other favorite live foods like rotifers, mysis, etc. Corals like live food too! I am sure I am leaving lots out.

Lots of DIY ideas, but if / when someone comes up with a mass produced clean and convenient way to supply a tank with this kind of live food, that will be somethin' !

 

[Paul B]

Besides live worms the closest thing have is clams which I buy live in a supermarket or fish market.

Live salt water fish fry would be the absolute best food as that is what most fish eat in the sea. I have spoken to fish food manufacturers for years but I don't think they are that easy to collect in the quantities needed for wholesale sale.

 

[SDK]

An easy way to acquire, cultivate, and feed a variety of live foods would be perhaps the single biggest positive development in the hobby since, I dunno, salt mixes?



Lots of DIY ideas, but if / when someone comes up with a mass produced clean and convenient way to supply a tank with this kind of live food, that will be somethin' !

White Worms and Grindal Worms both fit this bill pretty closely. I culture in such a way that I’m pulling a plastic disc out of the culture and dipping it into the tank. Just as fast to feed as pellets or flakes and they just need a few minutes per week of attention.

Before I had kids there were times when I had upwards of 40 tanks running. With a couple of tubs of each going I still had worms overflowing to the point where I was giving them away to local hobbyists. They are definitely worth the short money and small amount of time to get started...

 

[Daniel@R2R]

Great read! Thanks Steven!

 

[Brew12]

Great read! Thanks Steven!

Read? ;Wideyed
We know you only look at the articles for the pictures!

But thanks!

 

[drstardust]

Great stuff! I'm excited to see which direction things will go as more and more people start doing this

 

[Paul B]

This Idea had been around for 20 years and more people haven't caught on yet.
People will keep medicating their fish even though it is counter productive.

 

[drstardust]

This Idea had been around for 20 years and more people haven't caught on yet.
People will keep medicating their fish even though it is counter productive.

Maybe. Maybe not. If not medicating gets enough of a following it may become mainstream. For it to get a following it will have to yield better success rates for the masses than medicating.

PS got your book and love it so far.

 

[Paul B]

This one paragraph in Brew's article should convince some people:
Quote:

On top of that I found some information about the Seattle Aquarium and some fish health issues they had. Starting in 2012 they no longer used prophylactic treatments. By 2015 they had cut their fish mortality rate by over 80%.

If it works for the Seattle Aquarium and me, whats not to like. Of course the Seattle Aquarium stole the Idea from me, but they won't tell you that.

Drstardust, I am so glad you are loving my book so far. I know it's a nail biter.
(The MS Society will also be happy as all proceeds will go to them)

 

[Lasse]

When I took a class in Fish health at the University of Gothenburg back around 1985 - this figure was the first we had to learn (from Brew´s article)

​

This is nothing that Brew12 invent just now for this article - it have been the basic figure to describe the host/pathogen relationship for decades.

When the smallpox hunted down millions of people around Europe in the eighteenth century - there was some that did not get the disease - milkmaids. They was know for their smooth skin, not destroyed by scars from smallpox. The reason for this was that they where infected by another similar virus - cow-pox - nor very virulent for humans and the immune system built up for cow-pox was active against the more - for human - virulent small-pox viruses. In fact - it was from the cow-pox virus the first vaccine was developed ( vaccine from Latin word for cow - vacca.)

An adult human normally carry around approximately 2 kg of different microorganisms, mostly in the digestive system - many of them are facultative pathogens. It is first the last years we have been able to understand how important these bacteria/microorganism ecosystems are for our well being and development of defense systems against other pathogenic microorganisms.

Let us take an example from my own life. My digestive track contain a lot of bacteria that would kill me directly if the come out in my body cavities - outside the digestive tract. This is normal for all living things with a digestive tract - it is not special with me. What´s special with me is that I have has some narrow passages in my gut that now and then give me volvulus. Because of this - some of my bacteria from the gut can become life-threatening for me if the intestines burst because of a acute volvulus.

If the doctors (and I) had the same approach as people advocating for prophylactic treatment of our fishes - they would give me metronidazole every day - because it is an effective antibiotic against this type of anaerobic bacteria that can be life treating to me - they would also order me to only eat bacteria free food. If my gut not contain these facultative pathogens - I will not be sick if the intestine burst. But of cause it does not work that way, the antibiotics is not species specific, the stress -such a treatment will give me - will push me closer to disease - the treatment (in case of) will kill me faster than the time it takes for my next volvulus coming up. Instead do I have to live with my facultative pathogens and try to manipulate my precondition instead (not eat some food and so on) in a way that I don´t get any more volvulus. But if it happens - of cause it is time for active treatment again. You can say that my digestive tract is under observation QT for the moment

Sincerely Lasse

 

[RCeiver]

Seems somewhat annoying that you get to respond to comments but the person that wrote the comment can’t respond. Always have to have the last word I guess.

 

[Humblefish]

Practically speaking, how could one soak gut microbiota in fish food? Not everyone has access to clams and fresh seafood. LRS contains probiotics (which is excellent), but that alone is probably not enough to satisfy the dietary requirements for helping a fish develop immunity/resistance to pathogens.

 

[Lasse]

I´m normally only using frozen food containing whole animals (artemia, mysidae and copepods). In this way - they get the bacteria they need - not the same amount as with fresh and living food at each feeding but during time they get what they need. But it is not wrong to use fresh and living food too. My present aquarium (41 month) old have never get any dry food - frozen and food produced in the aquarium/refugium have been the only basic input of energy for the consumer in my aquarium. Sometimes I use fresh and living food - but too seldom.

I would love to farm black worms at home - @Paul B can you please post a manual or a link showing how to do it.

Sincerely Lasse

 

[Paul B]

Lasse, First of all, I enjoyed your post and learned from it. Second, you took a class in Fish health at the University of Gothenburg! I am impressed. We didn't have such classes, but that is very cool.

I actually took a class on Bubonic Plague. Today descendants of the survivors of one of the forms of Plague (there are three forms) are immune from Aids. Most plague victims died from a virus (as Aids is) and not, like popular opinion dictates from a bacterial infection, and not originally from rats. It originally came from China (like most of the cheap stuff many people buy) carried by gerbils. When the Gerbils died from the disease it turned to rats. Weird. ;Bucktooth

Practically speaking, how could one soak gut microbiota in fish food? Not everyone has access to clams and fresh seafood.

My good friend Humble. It is true that not everyone has access to fresh clams and seafood, but everyone who has fish and wants to keep them healthy has access to the internet.
I would not buy seafood on line but live worms are available on line and I have the same white worm culture going now for about ten years.

Every week or two I throw some stale bread with yogurt in there and they grow up the sides of the container and try to crawl in bed with me. I have so much that I scrape off the extra and stick them in my wife's underwear drawer just for fun
Whiteworms are in dirt which as we know is full of bacteria as is the worms gut.

The original worms were just a few bucks and now are practically free. That in itself is enough to satisfy the fishes needs for fresh bacteria as worms are the first way I got my fish immune in 1973 or so and they have been immune ever since.

If people have the time, energy and money to buy quarantine tanks, hospital tanks, and medications, they have the means to get some live worms, even earthworms are great.
If you get your fish on the proper diet with associated gut bacteria, there will be no need for all that stuff and fish will never get sick. (but I would not want to go there right now because we all know how that will end)

I also use LRS food every day and think it is the absolutely best "commercial" food out there, but as a commercial food "I" feel that although it does have Probiotic bacteria, which is great, it does not contain disease causing bacteria (which most people wouldn't want) but I do.

I feel that besides probiotics, which will vastly improve gut health, fish also need "occasionally" disease pathogens for continued immunity. It could just be me but as you know, my fish are immune from everything. Now maybe they would also be immune with just LRS food and that is a possibility, I don't know as I am not the God of fish or RAP music.

But we, or most of us, know that for any organism to "stay" immune from something it needs to be infected at least occasionally to it. No one knows how long that immunity will last although we can guess and I am sure it differs from a whale shark to an amphipod.

We humans get booster shots and I get a flu, shingles, pneumonia and measles shot every year because that immunity doesn't last.
It probably helps that I live in New York and rode the subway every day as those handrails are infected with every disease known on earth and more.
I am sure I picked up many weak forms of diseases in those years but I rarely get sick.

I have a theory (and I know no one wants to hear it, but I am going to say it anyway) I believe in a healthy, immune tank there are parasites and all diseases commonly associated with aquariums happily living in a communal relationship with the tank inhabitants. Those organisms sample some fish flesh and even go through their intestinal tract, maybe emerging out the other end unscathed, I am guessing here. But either way, the fish and pathogens benefit from this relationship which is normal and nature.

Our fish get sick "after" we treat them because we are killing the very things that were spicifically designed to keep the fish healthy. Like Duh!

How do we feel after we take antibiotics for maybe a tooth infection?

Fish in the sea are very healthy.

We call these things pathogens because they can kill us and the fish just like our own gut bacteria (and Oldsmobile's, guns, arrows, spears) can kill us (as Lasse stated so eloquently) But they also keep us alive as we won't live without bacteria, a large percent of us "is" bacteria and we all carry around parasites. Some rock singers have more parasites and some rock singers are parasites. ;Meh

We need to learn to live with these things and not kill them just as we should learn to live with algae as it is a "good" thing and not a disease as many people in this hobby feel.

Brew, I am very sorry for this long rant, but I was waiting for my wife to get up and I was bored and long winded. I will go and play with my worms now.

 

[Brew12]

First, let me apologize. Haven't been avoiding this thread but I'm in the middle of no where Arkansas for work this week and the hotel internet was down last night. Barely functional the rest of the time.

Practically speaking, how could one soak gut microbiota in fish food? Not everyone has access to clams and fresh seafood. LRS contains probiotics (which is excellent), but that alone is probably not enough to satisfy the dietary requirements for helping a fish develop immunity/resistance to pathogens.

Unfortunately, I do agree with this. Even worms aren't a great replacement for fresh seafood. And LRS only contains a single probiotic where science has identified at least 30 helpful probiotics and the method they use to improve fish health. I even found a report that listed one probiotic that needed to be avoided because it increased the odds of a different bacterial infection.

I suspect that fish which have been removed from the ocean long ago can benefit by eating the feces of fish that have come more directly from the ocean. Just speculation but it would make sense since we know all sorts of bacteria and parasites are excreted by fish and that they seem to enjoy feeding on each others waste.

 

[Lasse]

Use fresh frozen clams, shrimps or what ever whole fresh frozen marine organism instead of fresh if you can´t access fresh clams. They contain bacteria too.

Sincerely Lasse

 

[SDK]

I would love to farm black worms at home - @Paul B can you please post a manual or a link showing how to do it.

Sincerely Lasse

Blackworms are fairly easy to culture, just not in any kind of volume. I kept a spare tank of them going when I lived in Oregon. It was a three hour round trip to buy them.

Throw some gravel and a sponge filter in an unheated aquarium. Seed with worms and feed them. You will have a self sustaining population that you can use for occasional feeding as a "treat".

I suspect that with the addition of a chiller, heavy oxygenation and some strong current they would multiply more quickly. However, even if that worked, you then start getting into cost for electricity and time vs. return. I can keep them alive in the fridge for close to two months. It's easier for me to pick up a portion for $3 when I am at the LFS and just feed them out once or twice a week.

White Worms are similar in size, palatably and most likely nutritional value to Blackworms, but are much easier/cheaper to raise in numbers.

Having said that, Blackworms are not difficult to culture if you want to give it a try...

 

[Lasse]

Great stuff! I'm excited to see which direction things will go as more and more people start doing this

I do not know any reefer in Sweden that use prophylactic treatment as in the US. All I know use a variation of the thing outlined in Brew12´s article. Some use observation QT - some not but chose their fishes.

Sincerely Lasse

 

[MnFish1]

As responsible hobbyists we should all want to purchase and keep healthy fish and yet fish health can be a very contentious topic. If we all want the same thing, why do we argue about this topic so much? I feel it is because there is no easy answer to the question of when to consider a fish “healthy”.

Healthy, according to Merriam-Webster, has the following definitions:

1a: free from disease
1b: not displaying clinical signs of disease or infection
2: beneficial to ones physical, mental, or emotional state : conducive to or associated with good health
or reduced risk of disease
3: showing physical, mental, or emotional well-being : evincing good health

There, now I can rest easy because we all know what a healthy fish is. Ok, maybe not. I do think we can all agree that the end goal is to have fish that meet the 3rd definition by showing physical well-being. The problems arise when we look at the first 2 definitions. To explore how these first 2 definitions cause conflict, I want to address it from the perspective of a fish and the common parasite Cryptocaryon Irritans (Marine Ich).

Can a fish with Cryptocaryon Irritans be “free from disease”? Cryptocaryon Irritans is a pathogen which means it can be the causative agent of a disease. A disease is defined as “the condition of the living animal or one of its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms”. A pathogen only becomes a disease when it reaches a density or level of damage that causes symptoms. We know fish can act as hosts of Cryptocaryon Irritans while not showing symptoms so yes, a fish with CI can be “free from disease”. Definition #1a and b can be met for fish with and without Cryptocaryon Irritans.

What about definition #2? Is carrying Cryptocaryon Irritans “beneficial to ones physical state” or “reduced risk of disease”? As an obligate parasite, Cryptocaryon Irritans will do at least minor damage to a fish even if its immune system prevents that damage from reaching the level of a disease. It is also true that a fish without Cryptocaryon Irritans has no chance of it becoming a disease. That is about as reduced a risk as it can get. Based on this, a fish without Cryptocaryon Irritans would be healthier than a fish that carried it. Or would it?

To explore this further I am going to veer away from fish health and move into the world of human health. Is a person who has just received a measles vaccine healthier than a person without it? The Measles vaccine works by injecting a weakened strain of measles (pathogen) into our body so that our immune system can learn to fight it with a low risk of it reaching the level of a disease. Is a freshly vaccinated person who still has a weakened strain of Measles be considered healthier than a person with no Measles at all? At face value, no, they wouldn’t be, but that doesn’t tell the entire story. We vaccinate for a reason. It builds an immune response so that if a more virulent strain of Measles is encountered in the future the vaccinated person has a higher chance of not having disease symptoms than the person who is unvaccinated. From this perspective, exposure to a parasite does offer a condition that is “beneficial to ones physical state” and a “reduced risk of disease”.

Pathogen exposure in a fish does act much like a continuous vaccine. Instead of a lab weakened pathogen the immune system of the fish weakens the pathogen. This prevents the transition from a pathogen to a disease. The fish immune system is unlikely to completely eradicate the pathogen allowing for the continuous exposure needed to maintain the immune response. What is a healthy fish? Quite simply, a healthy fish is one that is not diseased, which means it is not showing symptoms of a pathogen. Fish with or without certain parasites and pathogens can both meet this definition. If we were to ask which is healthier, a fish with or without pathogens, the answer is less clear. I would argue that the fish that is free of pathogens is healthier in every aspect except future risk.

So why does a pathogen become a disease? This circular diagram does an excellent job showing the relationship that is likely to cause a pathogen to transition into a disease. One factor is how virulent the pathogen is. This gives consideration to how fast the pathogen reproduces and how much damage it can do. Gram negative bacteria tend to be more virulent than gram positive bacteria. Amyloodinium Ocellatum (Marine Velvet) is more virulent than Cryptocaryon Irritans. Another aspect is how susceptible the host is to each particular pathogen. Clownfish are more susceptible to Brooklynella than Angelfish are. Wrasses are more resistant to Cryptocaryon Irritans than Acanthurus Tangs are. The health of the fish also comes into play. Is it injured or suffering from malnutrition? Does it have genetic issues that reduce its immune system response? And then there are the environmental conditions or stressors. How is the water quality? Is the system temperature stable? Does it have aggressive or incompatible tank mates? Is the tank over or under stocked? These all come into play for a diseased fish.

I think it is important to emphasize the definition of a disease - the condition of the living animal or one of its parts that impairs normal functioning and is typically manifested by distinguishing signs and symptoms. As the circular graph shows, a fish can have symptoms of a disease without a pathogen being present. Stress alone, in a fish that is susceptible to stress, can impair normal functioning behaviors of that fish. A wrasse may not be considered susceptible to Cryptocaryon Irritans but with enough stress and a high enough number of parasites in the system a wrasse can show disease from the parasite. An extremely virulent pathogen combined with a susceptible host can lead to disease even in a stress free environment. And finally, if you have a susceptible host, highly virulent pathogen and adverse stressors, your fish is almost guaranteed to have those pathogens become a disease.

How do we reduce how virulent a pathogen is? The average hobbyist isn’t going to genetically modify that pathogen to make it less virulent as is done for vaccines so we can cross that one off the table. One option we do have is to eradicate as many known pathogens as possible. A pathogen that isn’t present offers no risk to the host. Copper and Chloroquine Phosphate can eradicate Cryptocaryon Irritans and Amyloodinium Ocellatum. Praziquantel can eradicate flukes, Turbellarians, and some internal parasites. Metronidazole can eradicate Brooklynella, Uronema Marinum, and other internal parasites. For this to be effective it is important to quarantine everything and prophylactically treat every fish that goes into your system. Remember, just because a fish isn’t showing symptoms does not mean it isn’t a carrier. Just like all things in life, prophylactic treatment does have its down sides. It requires a separate hospital tank to treat fish. It requires medications which are not available in many parts of the world without a veterinarian’s prescription. It requires quarantining everything wet, not just fish, as fish pathogens can be introduced via inverts and corals. If your bio-security fails then you have to remove and retreat every fish along with a fallow period to re-eradicate the pathogens. Chemical treatments are stressful on fish and weaken their immune system so while we can reduce the threat from the target pathogen we are increasing their vulnerability to other pathogens.

We do have other options to reduce the virulence of pathogens other than just eradication. We can reduce the number of free swimming parasites by installing UV filters. They must be properly sized and have the correct flow rate for the application. Ozone systems can be used to kill parasites and bacteria that pass through the filtration system. Diatom filters will mechanically remove free swimming parasites to help reduce the amount that can re-infect fish in the system. Free swimming parasites can be consumed by corals if they are captured. Peppermint shrimp have been proven to eat the eggs of some flat worm related fish parasites. Our closed systems have some disadvantages compared to the open ocean but we should do our best along these lines.

What can we do to reduce environmental stresses? Maintaining good water quality is important. This doesn’t mean we have to do large water changes although that is one option. We want to make sure our biological filter is well established prior to adding fish to prevent toxic ammonia from building up. A properly set up skimmer will help keep water clean. Activated carbon and/or hydrogen peroxide help break down and remove organics from the water column. We can use redundant heaters on controllers to help minimize the chance of a temperature spike. We should have a plan on how to keep our systems stable during a prolonged power outage. We should ensure we have spares of our critical components to keep the fish alive and healthy if we experience an equipment failure.

We also need to consider how we stock our tanks. With some exceptions I feel we should stock our tanks from smallest to biggest and from most peaceful to most aggressive. The size of our systems should dictate which fish are and are not appropriate. Even a Dwarf Angelfish will not do well in a 2.5g nano. We should consider fish compatibility. It may not work to stock peaceful fish with highly aggressive fish. Some species of fish will not tolerate others and some fish are intolerant of conspecifics (same species).

What can we do to reduce the susceptibility of the fish to act as a host to pathogens? The impact of gut microbiota on the fish immune system cannot be overstated. Ideally, we would all feed fresh, never frozen seafood straight from the ocean. This isn’t realistic for most of us. Regular feedings of high quality frozen food can boost fish health. If you don’t feed live foods, it is worth considering using foods with probiotics added to them. Probiotics are now available in some frozen and pellet foods. Not every feeding needs to use them, but consider using them at least on occasion. A variety of probiotics would be even better as they each may have a different way of impacting the fishes immune system.

Visual observation can also play a part. You may be able to determine if a fish is showing signs of a disease if you can monitor it prior to purchase. If you order from an on-line supplier a QT can provide a chance to do an observation after receipt. It also allows a potentially weakened fish the chance to feed and build health before having to compete with tankmates for food and space.

My desire would be that everyone in the hobby would take a holistic approach to fish health. We would all design redundant systems designed around good filtration and steady parameters. We would never experience those challenges in life that cause our husbandry to slip. We would stock fish appropriately and not put an Annularis Angelfish in a 75 gallon system or put 3 Acanthurus Tangs in a 150g system. We would all stop by the ocean on our way home from work to collect food for our tanks each day. Obviously, this isn’t going to happen. Instead, I’ll ask this. Keep these ideals in the back of your mind as you build and stock your systems. Be honest with yourself and how you will maintain and feed your system. Think about the circular diagram and how susceptible your tank will be to disease based on your plans. Ideally, we will be as far from the center of that chart as possible. If we succeed in that, we will likely never have a fish disease issue.

*All pictures used in this article are mine and used with my permission.

Excellent article.

 

[Humblefish]

Unfortunately, I do agree with this. Even worms aren't a great replacement for fresh seafood. And LRS only contains a single probiotic where science has identified at least 30 helpful probiotics and the method they use to improve fish health. I even found a report that listed one probiotic that needed to be avoided because it increased the odds of a different bacterial infection.

I don't doubt this can work IF coupled with a tool that eliminates free swimmers. However, fresh seafood can be hard to find in flyover country, and live blackworms costs $60 per 1/8 lb shipped and are subject to ever changing availability. (Most LFS do not carry live blackworms, and most Americans are not going to culture their own worms.)

On the contrary, seafood seemed to be everywhere in Europe when I lived/traveled there. Because it is such an important part of their diet, and you are usually never too far from the coast. Europeans are also typically more patient people, and willing to go that extra mile. Most Americans want everything quick & easy.

So from a practical standpoint, I don't see how this is ever going to work for mainstream American hobbyists. You have to really be dedicated to making it work. I watch public aquariums QT using copper + formalin with a ~ 80% success rate. 5-10 years later the fish are still in their displays (unless cross contamination or some other accident occurs.) No cancer, no destroyed immune system, etc. Of course, not every fish can tolerate that strong of a chemoprophylactic treatment, but it's hard to argue with the overall numbers. Makes me feel like we are constantly trying to reinvent the wheel when they figured it out long ago.