It is popular knowledge that every living creature is either a herbivore, carnivore, or omnivore. 

But have you ever wondered where our little aquatic friends- the fish truly belong?

In fact, for a very long time, I used to. Then I had to go find out and write down my findings to inform and empower you.

In the case of fish, it appears that no one is sure as to which feeding habits they prefer. 

Are Fish Herbivores

Are they carnivorous, herbivorous, or omnivorous?

Do they live solely on the water all year long?

Research has shown that there are about 34,000 different species of fish in the world today. Thirty-four. Thousand. All different.

Do you honestly think you could lump them together in one category, as if to say, “Hey there, be a good vegan and eat plants? That’s all you get?”

Fish species need a combination of protein, fat, vitamins, and minerals in their diet, albeit in varying proportions.

The different feeding habits of fish are that they get the optimum nutrition they need, no matter what category they fall in. That is, whether they are carnivores, herbivores, or omnivores.

  • Carnivores: this type of fish consume a meat-based diet.
  • Herbivores: these consume plant-based foods.
  • Omnivores: they consume both plant and meat-based foods.

Like humans, the various fish species have refused to be boxed into just one category; the only difference is that humans can make choices, but the fish don’t.

This is saying that, while preference may vary due to dietary needs, all fish conveniently occupy the 3 categories of feeding.

“Each according to his needs.”

The diversity in their feeding habits and dietary preferences is what keeps the aquatic ecosystem balanced.


Carnivorous animals rely on the flesh of other animals for their food. 

It happens to be the same with fish- they feed on other water animals’ flesh/meat.

They are also called predatory fish, like the big bullies of the water kingdom.

Their diet consists of other fish, worms, insects, snails, shrimps, etc.

These fish species lean towards this category because their digestive systems are unable to process and digest vegetables. I am thus causing them to depend on the prey for meals. Carnivorous fish require between 45%-75% protein in their diet.

Predatory fish get their food supply by;

  • Hunting down prey (this is common with sharks).
  • I was trapping them with baits.
  • Scavenging. The scavengers feed on any dead water animal sunk to the bottom of the sea or aquarium tank. 

Due to the predator/prey situation, smaller fish have to always be on the lookout, ready to escape. If not, they’d likely end up as dinner for one of the bigger fish.

As I stated earlier, the numerous fish’ feeding habits always provide an advantage to their habitat. The scavengers keep the sea clean and prevent the decaying matter of dead animals.

  • Adaptive Features of Carnivorous Fish

All living organisms possess adaptive features that enable them to take advantage of their environment. 

The main aim of the adaptive features is survival.

Some adaptive features of the carnivore fish include:

  1. Aerodynamic body for fast swimming
  2. Large stomach to contain prey
  3. Largemouth to carry chunks of food
  4. Sharp and pointed teeth to tear apart the prey
  5. Bigmouth to hold big prey
  • Examples of Carnivorous Fish

Some carnivorous fish include:

  • The shark
  • Barracuda
  • Billfish
  • Tuna fish
  • Salmon
  • Pike fish
  • Piranha
  • Ariana
  • Pufferfish
  • Butterflyfish
  • Bass fish, etc.


The herbivore category is like a direct opposite of the carnivore. The herbivorous fish derive their meal from plant materials: vegetables, fruits, plants, and microorganisms like bacteria, fungi, green and brown algae.

Because vegetables comprise most of their meal, there’s a large amount of fiber in the herbivore’s diet. The digestive systems of fish in this category are built to suit their nutritional needs.

Herbivorous fish mostly find their food by;

  • grazing
  • scraping algae and fungi off rock matter.
  • Adaptive Features of Herbivorous Fish

Some features that help the herbivorous fish feed well are:

  1. Flat teeth to grind food
  2. Smaller stomach compared to the carnivores
  3. Longer intensities: vegetables take a longer time to digest.
  • Examples of Herbivorous Fish

Some examples of fish in the herbivorous category include;

  • Surgeonfish
  • Parrotfish
  • Greenbone
  • Acanthurus nigritude
  • Black triggerfish
  • Caribbean reef sharks
  • Green sea turtle
  • Dugong
  • Grass, carp, etc.

The herbivorous fish are highly essential to maintaining a sound ecosystem within the aquatic habitats.

You might ask, “how?”

What happens is that these fish eat the brown and green algae to prevent excess supply within the sea/freshwater.

The presence of excess algae results in oxygen depletion within the habitat; this can lead to massive death of water animals, affecting humans.


Most fish are omnivorous. In this case, they share a trait with highly omnivorous humans, as well.

However, it is not split down in the middle. The fish species in this category do not necessarily need to consume an equal proportion of plant matter and meat.

Some fish require a more meat diet than plant-based, while others need more plant than meat in their meals.

The saying “different strokes for different folks” also holds in the aquatic realm.

There’s a high concentration of omnivorous fish in freshwater habitats because there’s a presence of both prey and plant materials, which are essential for their diet.

Because these fish can eat meat and a plant-based diet, their digestive systems possess similarities to both the carnivores and herbivores.

Omnivorous fish have a reputation for finding food due to opportunity. They are not necessarily hunting actively but will consume whatever is available.

I think the fish in this category are super cool. Just imagine: having the ability to adjust to any situation. 


Simply because their feeding habits are tolerant!

A superpower if you ask me.

  • Examples of Omnivorous Fish

Some examples of the omnivorous fish species are:

  • Carp
  • Buffalo fish
  • Minnows
  • Sunfish
  • Barb
  • Herring
  • Sardine
  • Goldfish, etc.


 If you’re the kind of person I believe you are, then every new knowledge is exciting to you. You care about wildlife and often wonder what goes on below ground level.

Then this piece was written primarily for you.

The various fish species’ feeding habits help keep clean their aquatic habitats and balance the ecosystem. However, the progression of things underwater does not relate to keeping fish on land.

If you’re considering building an aquarium, or fish pond, you must know what fish belongs to which category.

Then, they have to be separated. Keeping the predatory fish(carnivores), herbivorous, and omnivorous species together is never a good idea.

You ask why? Here are the reasons you shouldn’t keep the carnivores, herbivores, and omnivores together:

  1. The predators are likely to eat the other fish and each other.
  2. They require different diets.

Again, if you’re going to rear fish, you must take note of their dietary preferences. If fed the wrong things, the fish may begin to die of malnutrition- which is precisely what you want to avoid.

Most people out there are still wondering what fish eat. But you, by some stroke of luck or sheer, will have stumbled upon this article to guide you.

You have read this piece, now spread the knowledge!