Aquarium Fish Food Types and Nutrition 5

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As you may expect, different fish have different diets. Commercial foods contain more nasty things than you may know about, and some fish have very specific dietary requirements.

So how do you choose what food to feed? This in-depth article covers it all. (Including those hard to pronounce things on the ingredients list you don’t recognize!)

Types of Fish

In general, there are carnivores (fish that eat animal matter), omnivores (fish that eat both animal and plant matter), and herbivores (fish that eat plant matter). But there are many specialists. For example

  • In the wild, Oscars eat mainly snails and invertebrates, eating fish only when possible or on occasion.
  • Bettas are carnivores, but more specifically they are insectivores. These are animals that eat entirely invertebrates, in this case insect larvae or any that are unfortunate enough to hit the surface of the water.
  • Oto cats are strict herbivores, requiring live algae in their diet. This makes them limnivores.
  • Gar eat entirely fish, thus making them a piscivore.
  • Red tailed catfish are decidedly biased tword eating fish and shrimp but they are known to eat fallen fruit as well.

Obviously, since there are so many different types of fish there are many types of fish food out there. Not only do we have to keep the fish’s diet in mind, we have to think about how they eat.

Methods of Eating

In general, there are top feeding fish, middle feeding fish, bottom feeding fish, and grazers.

  • Top Feeding Fish: Bettas, gouramis, hatchetfish, and African butterfly fish all look to the top to feed.
  • Middle Feeding Fish: Tetras, barbs, South American cichlids, Damsels, Clowns, etc. all feed in the middle of the water column.
  • Bottom Feeding Fish: Corydoras, loaches, and Jurapari all sift around the aquarium floor for food.
  • Grazers: Loricariidae catfish, some loaches, tangs, some African cichlids, and many blennys graze for food on surfaces in your aquarium.

So what type of food is best for each type of fish?

Aquarium Fish Food Types

1. Dry Commercial Foods


Flaked foods are floating diets made from fish meal, squid meal, brewers yeast (a source of B vitamins and protein), soybean meal, and fortified with vitamins and minerals.

They also have a short lifespan. Once the package is opened, they only retain their nutrition for about a month. So only ever buy what you’ll go through in 30 days.

These are a good staple for almost all fish commonly kept but especially so for those who eat at the top of the aquarium. Suitable for fresh or saltwater

Crisps are a low-dust food that is nutritionally identical to flakes, only formed into an extremely thin disc. This reduced waste in the tank, also good for most fish.

Suitable for fresh or saltwater.



Granules are like pellets but smaller. They are good for small cichlids, middle-feeding fish, and some bottom feeders like loaches. Most granules sink.

Suitable for fresh or saltwater.



Pellets are made from a paste passed through an extruder, cut into cylinders and dried.

These are ideal for larger fish who need more substance in their diet. Goldfish, koi, medium-large cichlids all should be fed pellets.

Some fish, like bettas, are small but still need pellets because they are easier to digest. Some pellets are made to float, others are made to sink.


Discs are sinking foods usually plant based and aimed tword sucker mouthed catfish or algae eaters. There are also protein based tablets for loaches or fish who prefer eating off the bottom.

Suitable for fresh or saltwater fish.




When choosing commercial foods it is important to look at the ingredients list. They are listed by weight before the food is cooked, so you don’t want to see much “filler”. Filler is stuff that is cheaper than actual meat or plant matter, but still technically fits into a fish’s diet.

You also want as few carbohydrates as possible. Things like potato are used to help a fish feel full, however it does not provide much nutrition and do not spare protein for tissue building. The energy is also not stored by fish, which is why fish on a flake/dry food diet always act like they’re hungry.

So let’s look at some of the more popular ingredients.

The good

Fish meal is made from the leftovers of commercial fishing. It is dried and ground up into a powder (often after being cooked). It is a source of amino acids and generally an good ingredient to see. However, whole fish meal is superior.



Shrimp meal is along the same lines as fish meal, only it contains pigments which bring out a fish’s natural color. It comes from shrimp not “suitable” for human consumption.


Squid meal is a high quality protein source that also includes many vitamins and minerals. It is generally made from leftover squid viscera including eggs and testes.


Earthworm meal is made from commercially raised nightcrawlers. They are an excellent source of protein and fats for many fish, especially cichlids and is high in Vitamin D.


Spirulina is a blue-green algae and one of the most nutritious things on earth. It is an excellent source of vitamins A, B1, B2, B6, B12, C, E, beta-carotene, essential fatty-acids, 8 amino acids (proteins) and minerals.



The bad (ish)

  • Wheat flour is a source of carbohydrates, which as we previously discussed is not very good for fish.
  • Soybean meal is high in protein but also carbohydrates and phyto-estrogen. It is not very desirable compared to other sources of protein in my opinion, though it is highly used.
  • Wheat gluten, used mainly as a binder.
  • Feeding oat meal, another big carb.
  • Potato protein, more carbs.
  • Sorbitol, made from corn syrup.
  • Inositol, more carbohydrates, though not a sugar.

Notes On Vitamins, Minerals and Preservatives

Vitamins and Minerals

  • Niacin: Vitamin B3, which is an antioxidant.
  • L-Ascorbyl-2-Polyphosphate: A stabilized form of vitamin C. This is important for bones and teeth, healing, and a fishes immune system.
  • Riboflavin-5-Phosphate: (aka riboflavin) is vitamin B2. B2 is important for metabolizing fats, carbs, and proteins.
  • A-Tocopherol-Acetate: Vitamin E is another antioxidant. Also used as a preservative.
  • D-Calcium Pantothenate: Vitamin B5. This is required to synthesize coenzyme-A, which oxidizes fatty acids.
  • Thiamine Mononitrate: Vitamin B1 is important for neurological health, immune system health, growth, and digestive health.
  • Pyridoxine Hydrochloride: Vitamin B6 aids in proper growth.
  • Vitamin A Palmitate: Vitamin A, a carontenoid. This an antioxidant and brings out the color of fish. It is also important for stressed fish, and the development of bones and scales.
  • Menadione Sodium Bisulfite Complex: Vitamin K is essential for proper blood coagulation.
  • Biotin: Vitamin H, important in preventing anemia.
  • Cyanocobalamin: Vitamin B12. This is important for energy (as with all B vitamins) and metabolizing foods.
  • Cholecalciferol: Vitamin D3. This is directly related to calcium and phosphorus absorption, which is important for skeletal health.
  • Manganese Sulfate Monohydrate: Manganese, a trace mineral required by all animals. It is used as a part of “fortifying” animal feeds with nutrition.
  • Zinc Sulfate Monohydrate: A mineral, Zinc, essential to all animals and plays a role in many functions.
  • Ferrous Sulfate Monohydrate: A source of iron.
  • Cobalt Nitrate Hexahydrate: A trace mineral.
  • Astaxanthin: A carotenoid, helps enhance the immune system.
  • Folic Acid: Vitamin B9. As with all vitamins in the B complex it is important for metabolism.


  • Tocopherol: Vitamin E, a natural preservative that is resistant to high temperatures, good solubility in fats and oils, an antioxidant, and a good alternative to BHT.
  • Ethoxyquin: A synthetic preservative also used in pesticides and making rubber. It has been approved as use as a preservative because it is believed that in such a small quantity it does not effect fish health, however extensive use in fish food has not been studied in depth. For now, we do not know enough about this preservative to know if it’s is 100% safe or not.

2. Freeze Dried Food

Freeze drying has been used to preserve foods for a long time. It is the process of rapidly freezing a food then reducing the surrounding pressure to remove the frozen water by sublimation. This preserves the food for a very long time. However, you do loose some vitamins in the process.



(pictured: freeze dried krill)

Freeze dried food is also more dense, packing more calories in a smaller amount of space.

Freeze dried foods should be soaked in water before feeding to aid in digestion and help prevent swim bladder problems. They are actually  good food when used as variety, however since frozen foods and live foods are readily available you should choose them over freeze dried.

3. Vacation Blocks

Vacation blocks, or vacation feeders, are foods that are put into the aquarium and are supposed to feed the fish for an extended period of time, usually a few days or a week.


However, they are made almost entirely of either calcium sulfate or something like agar agar. They hold very little actual food, thus giving little nutrition. In fact, many fish do not recognize the item as food and end up not eating anyway as the block dissolves into the water, fouling it.

Healthy adult fish, or at leas the majority of commonly kept species, can easily go a week without eating. Many people have had experience going even longer without food without any problems. So it is usually wiser to just skip the vacation food and not risk loosing your fish.

4. Commercial Gel Foods

Gel foods are typically made of the same ingredients that dry food is made of, only with fewer preservatives. It is bound by Carob bean gum (locust bean gum), agar agar, or gelatin.



Quality varies by brand, but some are certainly nutritious enough to consider a good staple for many fish. Some are sold frozen, some room temperature, and others are a dry powder you mix with water.

This type of food has a higher shelf life than flaked food (when frozen, up to 6 months). If the right brand is chosen, this is a great choice for food.

5. Frozen Foods

Frozen foods are whole and blended frozen food items, either by themselves or mixed with other ingredients.

There is frozen brine shrimp, bloodworms, glassworms, mysis shrimp, daphnia, krill, squid, crab, cyclops, and more.


There are omnivore and herbivore foods as well that include red and green algae, romaine lettuce, spinach, etc.

All of these are highly nutritious because a lot of the food is left whole and uncooked. Freezing does destroy a negligible amount of vitamins, but care should be taken to ensure the food is not freezer burnt.

Overall, frozen foods should always be incorporated into the diet if possible. They help mimic a natural diet and provide variety to the animals diet.

Frozen foods should be considered very high quality, and if you know what you are doing, a fish can be healthy and happy on a diet composed of entirely frozen, live, and fresh food. Before fish food and freeze drying was invented, this was all fish were fed!

6. Live Foods

Live foods are just that, alive! They retain all of their original nutrition but do have some drawbacks as well. Some live food should be considered extremely nutritious and always be given preference! Others, however, should always be avoided.

Live foods like blackworms, bloodworms, daphnia, brine shrimp, ghost shrimp, cyclops, copepods, etc.are all good choices for many fish.


(photo credit: Oliver Lucanus)

They differ vasty in sizes though so look that up before getting them. Example: Daphnia are very small and fed mainly to fry and fish with tiny mouths, mysis shrimp are medium sized and great for 3-5” fish.


  • Not cooked or frozen, so no nutrition is lost. Extremely nutritious!
  • Moving food stimulated a fishes appetite, especially picky or wild caught fish!
  • It gives mental stimulation to the fish to be able to hunt.
  • Invertebrates feel no pain, therefore removing some moral issues with live feeding.
  • Some things, like brine shrimp, vinegar eels, and microworms can be grown at home.


  • Some foods, like blackworms, can come from filthy sewage and nasty water. They can sometimes carry pathogens with them that can make your fish sick. Because of this, they should be purchased on the day of arrival and rinsed thoroughly.
  • They have a finite shelf life, often for less than a month.
  • They are not commonly carried, especially not by large chain stores.
  • If you order online, which you may have to because of their availability, they can become out of your price range.

The Case Against Feeder Fish

Feeder fish are another story. Feeder fish are a terrible choice for many reasons.


  • Cheap
  • Easily available
  • Many fish will eat them (not that they should!)


Feeder fish, especially goldfish, are pretty much guaranteed to have parasites. Internal or external, these can (read: will eventually) be passed to your fish!

Many feeder fish have a very low nutritional value, especially those that are not fed often.

Feeder fish can also bring other diseases to your tank like bacterial infection, fish lice, and fungal infections.

Fish are actually an unnatural food choice for most fish they are commonly fed to (Oscars, african cichlids, south american cichlids, etc.) and completely inferior to other choices like shrimp, krill, snails, earthworms, or crickets.

Some other live food considerations are crickets, silkworms, crabs, and snails.

7. Home Made Food

Home made food may be the best option for many fish keepers. It allows you to know exactly what goes into your food and where it came from. However, it can also lead to deficiencies if you are not educated on fish nutrition.

Still, home made foods are a good compliment to a diet of dry foods. Most home made food is a mix of fresh or frozen ingredients held together with a binder, typically gelatin or agar agar. Recipes vary depending on what fish is being fed, obviously, but here are some you may want to try at home.

1.5 oz crickets or roaches
1.5 oz superworms
1.5 oz maggots
1” sq frozen plankton
1” sq frozen brine shrimp
1” sq frozen mysis shrimp
1” sq frozen krill
1” sq frozen tubifex worms
2” sq frozen glassworms
2” sq frozen bloodworms
2” sq frozen daphnia
And optionally fruit flies
Mix with a blender and add to a standard (unflavored) gelatin base.

1 fillet of salmon or tilapia (cooked)
1 jars of baby food – peas (make sure peas/water are only ingredients)
3 tbsp canned pumpkin (no other additives)
1/2 red pepper (chopped)
2-3 leaves of kale (large middle stem removed)
1 tablet acidophilus
1 multivitamin tablet (crushed, I was out of vitamins!)
1/2-1 tsp garlic
1 cup spring water
1 tbsp agar agar powder (OR 2 packets of unflavored gelatin)
1/2 tsp koi clay (optional, I did not have any today, so I did not add it)

– Cook fish and soften kale and red pepper in some boiling spring water.
– Put all ingredients in a bowl. Add 1/2 cup spring water. Puree using a hand blender or regular blender.
– Boil a 1/2 cup of springwater in a pot and add the agar agar slowly. Pour the puree into the pot and mix well.
– Pour mixture into a baking pan and put in refrigerator to set.
– Cut it into into small cubes and transfer to a baking sheet. Put baking sheet in freezer until gel food is frozen.
– Put gel food into ziploc bags and freeze.

For more recipes, read: DIY: 5 Simple Fish Food Recipes

Common Mistakes in Fish Diet

Many fish are fed inadequate diets, resulting in stunted growths, parasites, vitamin deficiencies, and worse! By far the worst fed fish I know of are cichlids.

So here are some commonly wrongly fed fish.

Oscars are often wrongly fed diets offeeder fish and pellets. This is wrong! They naturally eat snails, freshwater shrimp, and the occasional fish.



Bad foods

  • Feeder fish
  • Beef heart, or any land animal. In excess this food is too high in fat and cholesterol.

Good foods

  • Ghost shrimp
  • Krill
  • Earthworms
  • Crickets
  • Pellets
  • Orange (small amounts)
  • Zucchini (small amounts)
  • Snails

More on Oscar diets

These fish will absolutely eat feeder fish, but that is only out of desperation, conditioning to do so, or territoriality! Never feed them fish!

Bad foods

  • Feeder fish
  • Good foods
  • Herbivore and omnivore pellets
  • Algae Discs
  • Zucchini
  • Algae

Species profile

Another fish who will gladly eat feeder fish- to their detriment!

Bad foods

  • Feeder fish

Good Foods

  • Bloodworms
  • Algae discs
  • Algae
  • Zucchini
  • Mysis shrimp
  • Pellets

Species profile

Puffers greedily eat any fish small enough to fit in their mouths. But that’s not a good thing! They also need to be fed snails to wear down their teeth.

Bad foods

  • Feeder fish
  • Meat like beef

Good foods

  • Snails (very important!)
  • Shrimp- any kind
  • Bloodworms

Sources and Guides

How to raise your own foods
Brine shrimp
Vinegar Eels
Micro worms

General Good Reads and My Sources
A different perspective on preservatives
A really neat video about how fish flakes are made
Vitamins and their importance
Common live foods
Feeding Habits in Fish

Editor’s Note: This article was written by our latest contributor here at Home Aquaria, Victoria Murphy.

Victoria is a very active member of the fish community on Tumblr and we’re delighted to have her here on Home Aquaria. With a monster post like this, who wouldn’t be?

Join us in welcoming her in the comments section below or follow her on Tumblr here.

About Victoria Murphy

My name is Victoria Murphy and I run a fish oriented animal blog on tumblr ( I've been keeping freshwater fish for 7 years and work at a pet store specializing in freshwater and saltwater fish. I currently run 7 planted freshwater tanks and 1 FOWLR saltwater tank.

5 thoughts on “Aquarium Fish Food Types and Nutrition

  1. Reply danny grantham Oct 7,2014 4:14 am

    Good read. Fish do have different diets and needs. Whether it’s food or mixing fish types it is important to do the research first. I purchase my fish foods based on dietary requirements and feeding level. I always read the ingredients. I feed my fish sparingly, a couple times daily at the same feeding time.

    I keep African Cichlids, fancy swordtails, platies and Sailfin mollies. Some of the foods I use are Flakes, Spirula, Krill, Algae disc, Earthworms, Pellets and Granules. I have also use mosquito larvae but no feeder fish.

  2. Reply Meor Oct 11,2014 12:10 am

    Hi Victoria, great first post! Learned a lot from it.

    ..and Welcome to Home Aquaria! :)

  3. Reply Lizzy Oct 16,2014 8:31 pm

    Very awesome post! I learned so much and I’m looking forward to more from you!!

  4. Reply Noah V. Jan 26,2016 7:13 pm

    Wow, really in depth guide here. Thanks for going into so much detail. This is a great guide for tropical species, though I’m not sure that the rules also apply to goldfish/koi. I am curious what you think of this article about goldfish food as it relates to the carp family. It says apparently flake foods are a bad choice for them, but perhaps things are different from digestive system to digestive system.

  5. Reply Judith Feb 26,2017 3:35 am

    I have read about fish, algae eaters, emails are a no go, they can invade tanks.
    Everything about food and who eats what, and how many times a day, and keep regular schedule which I keep to within the hour. *Definitely one of my best reads yet.
    Size of tanks and filters, of which I have always thought the ground filter to me is a good idea, of which I have to look into more, (I heard of these 20 yrs and more when they where only in the thought stage before designed)
    All about plants live and fake.

    This site is an excellent score of information of which I have entered in bookmarks for future reference.

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