Are Fishes Herbivores, Carnivores, or Both?

Whether you’re new to fish petting or a veteran planning to own a new fish, it’s important to equip yourself with the right information. Knowing about fish diet, habitat, and everything else is necessary, or you might end up having opposite fishes in one aquarium.

Why is the fish diet the most important factor?

There are over 34,000 species of fish, and each species has its own dietary needs and requirements. Therefore, you can’t ignore the fact and feed your fish whatever you think is appropriate. Like other animals and living organisms, every fish has a mouth, teeth, and digestive tract. However, every animal or species in the world has a differently-designed body with tolerance to certain food types.

Therefore, we’ve created this guide for the aquarium owners and fish owners to help them know everything about their fish and their dietary needs. Besides, we will also guide you on combining different fishes in aquariums to avoid any undesirable consequences.

So let’s get into it.

Are Fish Herbivores, Carnivores, or Both?

In theory, the question sounds very simple. 

But in practice, it’s hard to answer for over 34000+ known fish and sea life species. You can not buy any fish and keep it in an aquarium believing that it will be vegan, will eat plants, or anything you will feed them.

Certain types of fish fall into certain categories. Just like the animals found on earth, fishes can’t be categorized as herbivores, carnivores, or omnivorous. You have to identify your fish type its dietary needs and then plan accordingly.

So the technical answer to this question is that fishes are carnivores, herbivores, and omnivores.

We will discuss each type, examples, and their dietary needs in a moment.

Different Types Of Fish

Fishes can be broadly categorized into three types be discussed in this blog. 

  1. Carnivore Fish
  2. Herbivore Fish
  3. Omnivore Fish


Carnivorous fishes represent the species of fish that feed on the meat. Like the carnivore category works in other living organisms, it also exists in aquatic animals and species. The meat-eater fishes or predators feed themselves on other fish species, invertebrates found in water, and insects. However, certain predator fishes are active hunters.

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How to know if a fish is a carnivore?

The carnivore fishes usually have some physical traits that indicate their hunting nature. They usually have larger mouths and large teeth to hunt their prey. Besides, most fishes are characterized by aerodynamic bodies that make them exotic swimmers to follow their prey or escape. You will usually see a large stomach of such fish to consume a whole fish at a time.

Most big carnivore fishes live in open water, and you’ll hardly find one in your local pet shop if you’re planning to get one. However, you can find smaller carnivorous fishes to keep in an aquarium and make sure to provide an ecosystem where different types of fishes can co-exist.

What do they eat?

The predatory fishes have a meat-based diet that varies from fish to fish. However, from a general perspective, the diet of such fish generally has 45% to 75% of protein. The carnivore fishes feed themselves either by live hunting, luring the prey, or feeding themselves on dead water animals in deep waters(scavenger fishes).


Here are some of the most popular carnivorous fish species known to human beings:

  • Great white shark
  • Tiger shark whale
  • Muskellunge
  • Megalodon
  • Bull Shark
  • Barracuda
  • Piranha
  • Salmon
  • Butterflyfish
  • Tuna
  • Billfish
  • Bass fish
  • Pufferfish
  • Pike fish
  • Red Lionfish
  • And a lot more.

The common type of carnivorous pet fish includes the following:

  • Piranhas are good pets, but these aggressive fish are best when kept alone or paired with other piranhas.
  • Arowana is a comparatively large pet with average life of 20 years. However, take care when feeding the fish as they’ve teeth everywhere. Besides, ensure the safety of the aquarium. as these fish are really good jumpers
  • Cichlid
  • Oscars have a famous reputation for having a bond with the owner. These fish happily eat shrimps, worms, small fish, etc. These require more attention, and they’re very curious about the outside world(aquarium surroundings).
  • Bettas also make a good choice as they have low maintenance, but betta males might be aggressive with each other.


Herbivores are the species that eat a plant-based diet. The herbivore fishes derive their diet from plants: vegetables, fruits, herbs, bacteria, fungi, and algae. Grazing and scraping algae and fungi 4are the most common way herbivorous fishes get their food.

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There are some adaptive features of the herbivorous fishes that can help identify these species. Vegetables and plant-based food have a lot of fiber, and the longer intestines help the herbivore fishes digest the plants by taking a long time. Since these fishes have to grind food, the flat teeth help them do that. The smaller stomach sizes than carnivore fishes is another distinct feature of herb-eating fishes.

What do they eat?

As already discussed, the herbivore fishes feed themselves on plant-derived food. Most of their food comprises plants, algae, fruits, etc. Fiber content is very high in herbivorous fishes’ diet. The herbivore fishes have smaller stomachs, so they can’t store much food. This makes them frequent eaters, and they eat several meals a day.

You can find these fishes constantly grazing on the rocks, wood, or areas with algae growth. When kept as a pet, these fish usually starve as there is not much choice in there. As a pet owner of herbivore fish, you can add supplements(seaweed, algae wafers, etc.) to meet their nutritional needs.


Common examples of herbivore fishes are as follows:

  • Silver dollars love to eat nuts, fruit, and miscellaneous vegetables in their diet.
  • Greenbone mainly feed itself on kelp(algae)
  • Green sea turtles love to eat seagrass and algae. You can find them scarping off the algae around coral leaves.
  • Parrotfish are beautiful creatures of water that consume algae as 90% of their daily diet.
  • Surgeonfish are also algae lovers
  • Mbuna are herbivore fish and love to eat any plant but mostly eat algae
  • Carps love to eat aquatic vegetation, algae, etc.
  • Dugongs are the herbivorous fish that feed on seagrass


The third type of fish is a hybrid one that eats a plant-based and meat-based diet. Some fishes are dominantly plant-eater and eat small fishes too. However, there are some omnivorous fishes whose diet comprises meat mostly. In other words, there is no set standard for meat and plant proportions in omnivorous fishes.

The omnivorous fishes are more abundant in aquatic life than pure plant or meat-eaters. The adaptive features of such fishes also support their plant-eating and meat-eating nature. Their digestive systems are designed to digest vegetables but might not be able to eat some plants and grains. These fishes find food according to the availability of opportunities. If they’re given the vegetables, they will eat that. And if there’s nothing to eat around, they will hunt their prey to feed themselves.

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What do they eat?

Life would be easy for you if you’ve kept an omnivorous fish as your pet. You can feed these fishes with specific fish flakes, algae wafers, frozen food, live food, or freeze-dried food at alternative times. All you need to do is create a balance of different food combinations to keep your fish’s eating interests lively. If you’re giving your food healthy food, it’s all good.


Here are some of the most popular examples of omnivorous fishes:

  • Barbs eat shrimp pellets, color flakes,  tropical granules, frozen food, live food, etc.
  • Bass fish have omnivorous nature and eat crayfish, baby birds, snakes, lizards, insects, frogs, etc.
  • Minnows will happily eat dead & rotting organisms, mosquitoes, crustaceans, algae, diatoms, fish eggs, etc.
  • Goldfish can be fed with live plants like water weeds, java fern, moss, insects, crustaceans, etc.
  • Buffalo fish can eat anything they get. From insect larvae to clams, and algae to plankton, give them anything.
  • Sunfish are popularly known as predators of jellyfish. But these fish are generous in eating algae, eelgrass, and zooplankton as well.
  • Herring love to eat crustaceans, small fish, mollusk larvae, etc. In plants, the adult herrings feed themselves on phytoplankton.
  • The common pleco can be omnivorous or carnivorous, depending on the species.
  • Leporinus spp. is omnivorous in nature, but the young fish usually eat a plant-based diet in abundance.

Final Words

We have answered whether fish is herbivore, carnivore, or both. Besides, the pet lovers who want to keep fish as their pet would have got insights about which carnivore, herbivore, or omnivore to pet. You will know about what to feed your fish and how to take care of the pet fish. We hope this information will help you in taking care of your fish very well.