Fish Nutrition – Short Bites

[Jay Hemdal]

Jay, and other fish keepers, is variety in diet the best option?? I have tangs, Lemonpeel and Chromis, I try to give “high” end variety everyday. Probiotics pellets, seaweed extreme, ocean nutrition 2, nori etc. even the frozen are 4 or 5 different cubes, brine, mysis, emerald, etc. I thought they were at a good healthy weight until I saw absolutely awesome dive videos on YouTube that showed Sailfin, my length but much more filled out, same with Hippo. I think this is maybe more muscle mass? Better variety of course? Any suggestions for better diets? I’m concerned about fatty liver disease.
Thanks, Debra

It's complicated. What you are doing is called the shotgun approach. The idea with it is if any one food is deficient in a nutrient, chances are, another food will cover what is missing. However, if any one food provides too MUCH of a nutrient, adding others won't help - this can be seen if a fish gets too many fat calories for example. Eating a salad doesn't do any good if you've already eaten gallon of ice cream (grin).

Fisheries scientists have developed single foods that meet all of certain fish's needs, so no variety is used at all. I have a clownfish that I have been feeding a single brand of pellets for 2 1/2 years and it looks better than any clown I've ever had. That said, some variety may be important for behavioral enrichment.

Fatty liver disease is tough to combat in captivity with predatory fish. Common wisdom indicates that lower calories would help limit it, but there seems to be other components as well - levels of various HUFAs for example. Feeding frequency may also play a role - predators fed every day often develop this faster.

Jay

 

[EricR]

Interesting article -- thanks.
Fatty liver disease note is especially interesting but not going to worry about it since I probably have that too, just based on my own, personal diet.

 

[ISpeakForTheSeas]

Excellent thread!

I have 2 questions-

1. Fatty-liver is commonly associated sugar consumption as well - could it be due to the fact that a lot of dry fish foods are filled with wheat, flour, corn and other fillers?

Moreover, it seems natural that the size of an aquarium plays an important role in fish health - meaning a large fish with barely any swimming room will obviously have more health issues compared to the same fish in a much larger aquarium?

2. What other impact do grains, fillers, corn, etc. have on the long-term health of aquatic fish?


I was shocked at how many 'high-quality' fish foods contain large amounts of fillers and grains.

Yeah, excess starches/grains can cause a fish's liver to work less or to stop functioning altogether (this typically impacts carnivorous fish more than omnivorous/herbivorous, to my current knowledge). The quotes below discuss a lot of the other questions you brought up, but I've also wondered about aquarium size and if we can encourage fish to be more active to prevent health issues like fatty liver disease;

The flours and starches basically provide calories that the nutrient dense meals, oils, etc. in the feed may lack while helping the pellets stay together in the water (so it's meant to provide the energy while the rest of the food provides nutrition), but you're right that these are not healthy in excess. The excess carbs from too much starch have been shown to cause a variety of different health issues and weakened immune systems (dependent on fish species, natural diet, etc.).* So, starches in moderation are fine, but when overdone, they definitely can cause issues. Whether or not TDO and similar pellets have enough starch to cause these issues is a fair question that would require some pretty intensive research to figure out. Based on the results TDO gives, I would assume that, if it has too much starch, it only has slightly too much (meaning that real issues likely wouldn't be seen for years).

My understanding is that newer (superior) pelleting methods don't require as much starch to keep them together as older methods do, but I've heard that older methods are still largely the norm for the fish keeping industry.

*Source:
https://www.researchgate.net/public...growth_glucose_metabolism_and_hepatic_enzymes

Pretty much every pellet on the market will contain grains of some variety (almost always to act as a binding agent to hold the pellets together; sometimes also to provide enough calories/energy to make the food an efficient feed) - if used in small enough quantities, it's not really an issue, but when there's too much grain (too many carbohydrates) it can cause some nutrition issues.

 

[MnFish1]

Excellent Article @Jay Hemdal

 

[Flame2hawk]

Have a FOWLR with tangs, Angels and variety of others.
TDO pellets in Am, followed by Kelp Nori (8% protein) and a frozen mix (PE Mysis, Sponge and assorted brime shrimp with beta glucan, Anglixir and selcon added in the early evening. Thoughts?

 

[MnFish1]

Have a FOWLR with tangs, Angels and variety of others.
TDO pellets in Am, followed by Kelp Nori (8% protein) and a frozen mix (PE Mysis, Sponge and assorted brime shrimp with beta glucan, Anglixir and selcon added in the early evening. Thoughts?

first - if your fish are doing well - dont change. Second, I tend not to believe in Selcon, betaglucan, and am not sure what anglixir is. I have never used any of these and have had success. Having said that - I don't seen any reason not to continue what you're doing except potentially spending more than you need to?

 

[Jay Hemdal]

first - if your fish are doing well - dont change. Second, I tend not to believe in Selcon, betaglucan, and am not sure what anglixir is. I have never used any of these and have had success. Having said that - I don't seen any reason not to continue what you're doing except potentially spending more than you need to?

The issue I've always had with Selcon is that when it first came out, the name implied it was somehow similar to Selco from INVE. Trouble is, Selco is not stable and needs to be refrigerated and then only lasts a month or so after opening. How then, can Selcon contain the same HUFAs but be shelf stable? I am dubious.....

Jay

 

[MnFish1]

The issue I've always had with Selcon is that when it first came out, the name implied it was somehow similar to Selco from INVE. Trouble is, Selco is not stable and needs to be refrigerated and then only lasts a month or so after opening. How then, can Selcon contain the same HUFAs but be shelf stable? I am dubious.....

Jay

As several other threads on R2R testify to - many suggest a benefit of a placebo. (Not saying this about selcon)

 

[Debramb]

I have to admit, as Jay said I am “shotgun” approach because of “old” thinking. Since the 80’s, there have been better advances in fish health, such as experienced people like Jay. I guess it seems as if variety in the ocean equates
Variety at home! My transfer to 125gL means new variety of fish, bonded pair of clowns (that I want fat and healthy) and a
Royal gamma so I have TDO large and small pellets ready to feed. I will check with Mike, Dr Reef at Quarrentined fish what he feeds. I appreciate so many opinions ‘cause I feel better about my fishes foods
Also, because of what Jay said, months ago, about frozen foods, refreezing, I now push the cubes out of pkgs to check for ice crystals before purchasing!
Debra

 

[Flame2hawk]

first - if your fish are doing well - dont change. Second, I tend not to believe in Selcon, betaglucan, and am not sure what anglixir is. I have never used any of these and have had success. Having said that - I don't seen any reason not to continue what you're doing except potentially spending more than you need to?

Angelixir has ingredients that mimic sponge. Thx

 

[Rocky Mountain Reef]

I'd like to hear what Mike ad Dr. Reef feeds as well.

 

[Rocky Mountain Reef]

I buy all my fish from Dr. Reef. I believe it says on their website that they feed Mysis and brine shrimp, but not sure if there is anything else

 

[Nano_Man]

Great thread from jay and from r2r members

 

[lion king]

I start with; 1st, researching the diet of the species in the wild. 2nd, base diet on carnivore, omnivore, herbivore designation. 3rd, offer fresh or bought fresh and frozen in small batches human grade seafood. Offering live macro algae when possible, as well as providing a mature tank with micro algae for grazing herbivores and omnivores. Some species will require the inclusion of live foods to survive long term, this is a special consideration for certain species. For expanded info on specifics in feeding predatory fish like lions and all scorps, eels, anglers, etc; click my name and "find all threads". I expand on information regarding thiaminese, the need of proper fats, feeding schedule, and how a carb dominant diet will promote fatty liver disease in predatory fish. Not only are lfs foods long dead with little to no natural nutrition left, but they also contain ethoxyquin which is a known carcinogen used as a preservation. The nutrition of these foods come from the chemical supplemental additives. Ethoxyquin is sprayed on the fish used for pet food after it has been separated from the fish to be used for human consumption, so it is not listed on the ingredients. Foods like LRS and Rods are the exception, along with any others that list human grade ingredients. Pellets and flake food contain wheat, soy, and various "meal" ingredients which should never be fed to aquatic life; read the ingredients as there are some acceptable exceptions, and some lfs have started manufacturing their own.

Oh and if you are a human that pays attention to what you eat; don't eat farmed fish, they are raised in chemical sewage for disease and algae control, growth hormones, and the tumors are just cut around.

 

[Debramb]

I start with; 1st, researching the diet of the species in the wild. 2nd, base diet on carnivore, omnivore, herbivore designation. 3rd, offer fresh or bought fresh and frozen in small batches human grade seafood. Offering live macro algae when possible, as well as providing a mature tank with micro algae for grazing herbivores and omnivores. Some species will require the inclusion of live foods to survive long term, this is a special consideration for certain species. For expanded info on specifics in feeding predatory fish like lions and all scorps, eels, anglers, etc; click my name and "find all threads". I expand on information regarding thiaminese, the need of proper fats, feeding schedule, and how a carb dominant diet will promote fatty liver disease in predatory fish. Not only are lfs foods long dead with little to no natural nutrition left, but they also contain ethoxyquin which is a known carcinogen used as a preservation. The nutrition of these foods come from the chemical supplemental additives. Ethoxyquin is sprayed on the fish used for pet food after it has been separated from the fish to be used for human consumption, so it is not listed on the ingredients. Foods like LRS and Rods are the exception, along with any others that list human grade ingredients. Pellets and flake food contain wheat, soy, and various "meal" ingredients which should never be fed to aquatic life; read the ingredients as there are some acceptable exceptions, and some lfs have started manufacturing their own.

Thanks for the info, will do better research on species specific diets.
Debra

 

[Finzin]

Fish Nutrition – Short Bites

Proper nutrition of captive fish is a very complicated subject. Virtually everything known about this topic is derived from fisheries science and therefore is related to growing fish for human food – where the fastest growth rate is most important. Long-term captive fish in aquariums have different needs. The following are some snippets of information regarding diets and feeding of aquarium fish, with the emphasis on giving information about the main issues, with the least amount of text.

Proper nutrition is vital to all animals. The fish in your aquarium rely solely on you to meet all of their dietary requirements, and their food must be provided in sufficient quantity to supply the energy they need in order to grow. The diet must also have the proper balance of fats, proteins, and carbohydrates, as well as the proper amount of vitamins and minerals.

On the other hand, too much food or food that is too high in calories will cause the fish to become obese. Not all fish have the same dietary requirements, and their needs even change as they grow. To top it off, over-feeding an aquarium can result in deteriorating water quality that will harm the fish.


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/

Using 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 any active fish diseases. Think of your pet dog – feeding it a great diet will do nothing to stop a flea or tick infestation if you take it for a walk in an infested field!

Adding vitamins or food additives to the aquarium’s water: Don’t do that. This just feeds the heterotrophic bacteria. Aquatic animals, if they uptake vitamins from the water at all, do so slower than the bacteria does.

True vitamin deficiencies: These are rare in fish. The two most common deficiencies are with Vitamin E and Thiamin (B1). These often need to be supplemented as they are not in great enough levels in many seafood items.

Food amounts: Some reef aquarists tend to underfeed their fish in order to try and limit nutrient and waste levels that would cause algae issues. This is not humane for the fish. Better to limit the number of fish in the reef tank instead. Some other aquarists may overfeed their fish. The one thing that they can do for their fish is to feed them, and some people take that to the extreme.

Fish not eating: Acute anorexia (where a fish suddenly stops feeding, or never starts feeding, and soon dies) is usually caused by some environmental issue; water quality problems, disease, transport stress or tankmate aggression. Chronic anorexia is a rarer problem, where the fish has apparently adapted well to captivity in all respects except that it does not show a normal feeding response. This can be due to the species’ natural history (only feeding on coral for example) or can sometimes be caused by collection with cyanide. Be sure to evaluate a non-feeding fish right away and take steps to resolve any environmental problems. Don’t fall into the trap of assuming the fish will begin feeding when it gets hungry enough, or conclude it must be eating something, just not when you are watching. A fish that does not actively pursue and consume food that you offer it is going to have problems surviving for the long term.

Fatty liver disease (Hepatic lipidosis): A major chronic health problem facing most long-term captive fishes is “fatty liver disease,” or liver degeneration. Fish do not assimilate fats well, so often, if a fish's diet is too high in fat, it will then be deposited in various tissues, especially the liver. Unlike with mammals, this fat is not readily usable during times of starvation. Even if food is withheld from a fat-laden fish, very little of the fat is ever reconverted into usable energy. Some fish do not show outward signs of obesity, especially sedentary species such as groupers and lionfish. In these, fatty liver disease may only be diagnosed after death, when sections of the liver will show oil droplets and pieces of the liver itself will float in seawater. With many animals, a period of acute anorexia can cause liver damage.

Fatty liver disease is most common in adult fish whose growth rate has slowed considerably. Younger fish tend to grow fast enough to minimize fat deposition—excess calories are turned into muscle tissue instead. With long-term captive fish, fatty liver disease is the leading cause of (or contributor to) death. Virtually every lionfish held in captivity longer than three years will show evidence of fatty liver disease upon necropsy.

Thiaminase: This is an enzyme that metabolizes or breaks down thiamine (vitamin B1). In high enough concentrations in food, thiaminase will create thiamin deficient diets in fish. This is a common, yet serious problem with predatory fish that are fed feeder goldfish, as goldfish are very high in thiaminase. Lionfish, piranha and oscars cichlids were commonly fed all-goldfish diets by home aquarists. Health issues in their fish were then very common; fatty liver disease in lionfish, pica in piranha (where they eat each other to try to get more thiamin). Fresh seafoods known to be high in thiaminase can be supplemented with thiamin. Conversely, aquarists can avoid feeding fresh seafoods known to be high in thiaminase.

The actual impact of thiaminase on a fish’s diet depends on three factors:
What proportion of thiaminase-containing food is fed to the fish
What the concentration of thiaminase is in the food item
How much vitamin B1 is already present in the food

Frozen foods: Food in the pet supply chain is not always handled very well. For decades, there have been issues with frozen fish foods being repeatedly thawed and refrozen while going from the manufacturing plant to your home. Each cycle degrades the product. It is really bad with brine shrimp...in that case, the subsequent refreezing causes large ice crystals that pierce the shrimp's body, allowing virtually all the nutrients to leak out.

Is there a hierarchy of things to try to avoid or minimize to modify the risk for fatty liver disease in captive predators? For example should all pellets that contain grains be avoided or is there a threshold when the grains become problematic. Is this more of a problem than inadequate or excessive HUFAs?
Over feeding and inadequate tank space seem to be major risk factors. From what was said I am assuming this is a problem even in large public aquarium displays. In my case Triggerfish are my main concern. I know there is little specific info for different fish species outside of aquaculture. Is there any more information you can impart regarding your experiences with public and large home aquariums and fatty liver disease? Or recommendations re articles,book chapters etc?I tried google scholar and as you said not a lot of info. Thanks for any additional guidance you maybe able to give.

 

[Jay Hemdal]

Is there a hierarchy of things to try to avoid or minimize to modify the risk for fatty liver disease in captive predators? For example should all pellets that contain grains be avoided or is there a threshold when the grains become problematic. Is this more of a problem than inadequate or excessive HUFAs?
Over feeding and inadequate tank space seem to be major risk factors. From what was said I am assuming this is a problem even in large public aquarium displays. In my case Triggerfish are my main concern. I know there is little specific info for different fish species outside of aquaculture. Is there any more information you can impart regarding your experiences with public and large home aquariums and fatty liver disease? Or recommendations re articles,book chapters etc?I tried google scholar and as you said not a lot of info. Thanks for any additional guidance you maybe able to give.

Not much is known about hepatic lipidosis in captive fish. You can’t diagnose it until after the fish has died, and even then you need to use a histopathologist’s report. Before I retired, I was working on a system that used water with different specific gravity to float liver samples in to to determine relative buoyancy - but I never finished the project.

Here is some additional text that I wrote about this in my fish disease book (still being developed):

What techniques are available to solve this problem? Nothing can be done for a fish once fatty liver disease has become evident. Prevention is the only course of action an aquarist can take. Simply putting the fish on a "diet" may not work, in that this may result in increased aggression towards other fish in the aquarium. The best solution is to avoid feeding herbivores diets high in meat proteins and to train carnivores to feed on low-protein, low-fat diets such as squid or gelatin diet. Also, avoid feeding any saturated fats to fish. Overall dietary fat levels should be less than 16% in actively growing fish and less than 9% in adult fish.
Vitamin E supplementation is often used in an attempt to prevent fatty liver disease and liver degeneration, which is one of the top chronic health problems of captive fishes. Even with vitamin E supplementation you can still see fatty liver disease issues, either due to vitamin E depletion as a result of feeding slightly rancid (peroxide containing) feeds, or because other aspects of the fatty acid metabolism incorrect, such as feeding cold water fish species to tropical fishes.

There has also been a theory that feeding freshwater fish to predatory marine fish will cause malnutrition and fatty liver disease. Most of the rationale behind this has to do with slightly different fat profiles between marine and freshwater prey fish species. Credence is given to the theory when so many marine aquarists report that they lost their lionfish to liver degeneration after feeding them live freshwater goldfish (See the next section for an alternative hypothesis regarding issues with feeder goldfish). In reality, they would have run into the same trouble had they fed any single fish species as a diet for their lionfish. Feeding carnivores too frequently can also cause fatty liver disease. The general recommendation is to feed larger carnivores only twice a week.

Jay

 

[ISpeakForTheSeas]

For example should all pellets that contain grains be avoided or is there a threshold when the grains become problematic.

There is a threshold - as is talked about in the link I shared earlier, in very small quantities, grains seem to be alright/mildly beneficial even for predators - but I don't know where the threshold is. To be safe, I would assume it's a low threshold.

 

[Finzin]

There is a threshold - as is talked about in the link I shared earlier, in very small quantities, grains seem to be alright/mildly beneficial even for predators - but I don't know where the threshold is. To be safe, I would assume it's a low threshold.

Do you think NLS meets this low threshold. It’s the 3rd ingredient. Doesn’t tell you much. I emailed NLS they said it’s proprietary info how much wheat flour was in their product and didnt tell me how they came to this amount or was it just based on the minimum amount needed to hold the pellet together. That would be my guess whatever that number is. I am leaning towards avoiding wheat all together do to lack of good definition of what is safe. On the other hand I hate to give up on an otherwise quality pellet like NLS.Any other recommendations or thoughts are appreciated.

 

[Finzin]

Not much is known about hepatic lipidosis in captive fish. You can’t diagnose it until after the fish has died, and even then you need to use a histopathologist’s report. Before I retired, I was working on a system that used water with different specific gravity to float liver samples in to to determine relative buoyancy - but I never finished the project.

Here is some additional text that I wrote about this in my fish disease book (still being developed):

What techniques are available to solve this problem? Nothing can be done for a fish once fatty liver disease has become evident. Prevention is the only course of action an aquarist can take. Simply putting the fish on a "diet" may not work, in that this may result in increased aggression towards other fish in the aquarium. The best solution is to avoid feeding herbivores diets high in meat proteins and to train carnivores to feed on low-protein, low-fat diets such as squid or gelatin diet. Also, avoid feeding any saturated fats to fish. Overall dietary fat levels should be less than 16% in actively growing fish and less than 9% in adult fish.
Vitamin E supplementation is often used in an attempt to prevent fatty liver disease and liver degeneration, which is one of the top chronic health problems of captive fishes. Even with vitamin E supplementation you can still see fatty liver disease issues, either due to vitamin E depletion as a result of feeding slightly rancid (peroxide containing) feeds, or because other aspects of the fatty acid metabolism incorrect, such as feeding cold water fish species to tropical fishes.

There has also been a theory that feeding freshwater fish to predatory marine fish will cause malnutrition and fatty liver disease. Most of the rationale behind this has to do with slightly different fat profiles between marine and freshwater prey fish species. Credence is given to the theory when so many marine aquarists report that they lost their lionfish to liver degeneration after feeding them live freshwater goldfish (See the next section for an alternative hypothesis regarding issues with feeder goldfish). In reality, they would have run into the same trouble had they fed any single fish species as a diet for their lionfish. Feeding carnivores too frequently can also cause fatty liver disease. The general recommendation is to feed larger carnivores only twice a week.

Jay

Thanks for your time and reply. Can you define low protein diet by a percentage? The gel diets I looked at have around 50 percent or more protein. When you say squid diet do you mean squid as the main protein source?What dose of vitamin E are you recommending? When you say large carnivore are you referring to 13/14 inch Trigger?