What Do Fish Eat In The Wild-Everything You Need To Know

Are you just wondering about “what do fish eat in the wild?” or you’re planning to feed wild fish? Or you’re having some fishes from the wild and curious if they eat the same food as the pet fish? Whatever is your reason to be here, I have gone through the same questions as you are now!

Then, I did some online and offline research to find the answer. Consequently, what did I found! Let’s see- What do Fish eat in the wild? (Both Freshwater and Saltwater)

  • Aquatic weeds
  • Grass
  • Mollusks (octopus, squid, snails, slugs, mussels)
  • Crustaceans (krill, crayfish, crabs, lobsters, woodlice, shrimps, prawns, and barnacles)
  • Other Fish (Dead or Alive)
  • The Eggs of Other Fish
  • Algae
  • Water Plants
  • Worms
  • Insects
  • Insect Larvae
  • Amphibians (frogs, toads, newts, and salamanders)
  • Kelp (Algae)
  • Detritus
  • Echinoderms (sea urchins)
  • Scavengers
  • Carcasses of Other Marine Animals
  • Plankton, Zooplankton, and Phytoplankton, etc.


Depending on the location and environment, the diet changes from one to another. Also, the diet of wild fishes can be different according to their feeding habit, like some fishes are Herbivores, Omnivores, or Carnivores.

Freshwater and Saltwater fish also has different food habit as per food availability.

Ocean, river, lake, or pond every water source has a diverse food source on their own. The fish from those area has different diet and taste.

So, there is no single uniform answer to the question of “what do fish eat in the wild“. Instead, we will talk about freshwater fish diets, especially fishes that are normally you will see around.

What do freshwater fish eat in the wild?

Fish in the Wild

There are a variety of fishes out there, and their diet also differs from one type to another. Depending on the different eating habits of wild fishes, we divide them into five groups. The five groups are-

1. Herbivores: Herbivorous fish whose primary food source is a plant or plant-based material, grass, weed, and algae, etc.

Some herbivorous fish are- Scats, Monos, Buenos Aires Tetras, Silver Dollars, The Common Pleco, Leporinus spp., Uaru spp., Oscars, Mbuna(rockfish), Goldfish, Bovines, Camelids, Molly, Farowella, Pacu, Tropheus. [Some of them are voracious and brackish fish]

What does herbivorous fish eat?

Aquatic Plants or plant-based material, Algae, Grass, etc.

2.Omnivores: Omnivore fish has the ability to eat both animal and plant material. Fishes which inhabit shallow waters and photosynthesis is possible; this freshwater fish can be omnivores. They also consider a general feeder.

Omnivorous fish are – Carp, buffalo fish, minnows, sunfish, catfish, Angelfish, Barbs, Danios, Festival, Goldfish, Guppy, Loaches, Platy, and Barb.

What does Omnivorous fish eat?

Aquatic Plants or plant-based material, Algae, Grass, specific types of grains, and meat foods are other fish, the egg of other fish, worms, insects, insect larvae, amphibians, etc. 

3. Carnivores: Carnivorous fish or Predatory fish which feed on meat and other fish. They swallow their food, and their digestive system can handle large pieces of meat. Carnivore fish can eat plants, but those provide no nutrition values to a carnivore fish.

 Carnivorous Fish: Acara, Archerfish, Bettas, Hatchetfish, Piranhas, and Oscar, etc.

What does Carnivore fish eat?

Insects, Insect Larvae, Smaller fish, blood worms, etc.

4. Planktonic feeder: These fish feed on Plankton. Small Fish and crustaceans eat plankton.

 5. Benthos feeder: This category of fish feed on decaying materials and dead. Also known as Bottom Feeder fish.

 Benthos or Bottom feeder fish are Plecos, Catfish spp., Botia Loaches, Kuhli Loaches, etc.


What Do Fish Eat In The Ocean

Ocean Fish

As per their environment and the fish classification-Herbivores, Omnivores, Carnivores, Plankton Feeder, and Bottom Feeder, ocean or marine fish feed on:

  • Other Fish/Small Fish (Dead or Alive) [Most of the marine fish are predator]
  • Mollusks (octopus, squid, snails, slugs, mussels)
  • Echinoderms (sea urchins)
  • Worms
  • The Eggs of Other Fish
  • Algae
  • Water Plants
  • Worms
  • Insects
  • Insect Larvae
  • Aquatic weeds
  • Grass
  • Crustaceans (krill, crayfish, crabs, lobsters, woodlice, shrimps, prawns, and barnacles)
  • Aquatic Weeds
  • Detritus
  • Scavengers
  • Carcasses of Other Marine Animals

Like the freshwater fish, there is no general rule on what different fish eat in the ocean. It varies to their type and the availability of the food they can get. Fish can change their diet according to their environment.

But, most of the ocean fish feed on another fish or other marine animals. Some saltwater fish also eat aquatic plants, weeds, and grasses.

We will talk about the details about the marine fish diet in another article. Let’s look at some specific fish’s diet in the wild (mainly fish from the freshwater):

What Do Oscar Fish Eat In The Wild

Oscar is an Omnivorous fish and lives in a tropical or subtropical area. However, they prefer meaty food in the wild. In nature, Oscar fish consume snails, shrimp, insects’ larvae, and other insects. Their diet highly consists of small fish, larvae, crustaceans, insects, and plant debris as per field observation.

What Do Goldfish Eat In The Wild

Goldfish are Omnivorous, just like Discus and Oscar. Goldfish’s wild diet consists of various plant matter, crustaceans, and insects. Goldfish are opportunistic feeders and will munch into the available foods. They can also eat eggs from other fishes or small water animals.

 What Do Tropical Fish Eat In The Wild

Depending on their type (Herbivorous, Omnivorous, or Carnivorous), tropical fish eat algae, aquatic plants, or plant materials. Predatory tropical fish feed on other small fish, insects, larvae, crustaceans, and water animals.

What Do Koi Fish Eat In The Wild

Koi are Omnivorous fish; they’ll feed on anything from plants to algae to small fish and insects. For better koi growth, they need vitamins, proteins, carbohydrates, minerals, and fat at the right amount. In nature, they keep it stable by hunting their required food. 

What Do Baby Fish Eat In The Wild/ What Do Fish Fry Eat In The Wild

Baby fish only capable of having food themselves at the stage called “fry.” Baby fish feed on plankton, small water insects, plants, tadpoles, small fish, etc. For newly hatched fishes feed on diatoms, protozoa, small algae cells, and other tiny water organisms.

What Do Discus Fish Eat In The Wild

Wild Discus Fish

Discus fish are Omnivorous. In the wild or nature, Discus fish eat a substantial amount of detritus and plant materials; however, they also search the bottom for the small crustaceans and worms. They may even have small insects and larvae from the bottom. As you can see, Discus is a bottom feeder.

What Do Small Fish Eat In The Wild

Small fish in the wild eat (who are capable of hunting foods) small shrimp, insects, fish eggs, other baby fish, etc. if they are carnivores, for small herbivorous fish will have plant, plant- matter, algae, plankton, etc. In comparison, the omnivorous small fish diet consists of both.

 What Do Molly Fish Eat In The Wild

Molly highly settled with algae, plants, plant-based matter, though they are Omnivorous fish. They also feed on puny invertebrates (Animals without bony skeleton or Backbone).

What Do Garra rufa Fish Eat In The Wild

Garra rufa or red Garra rufa, also known as nibble fish and doctor fish, Garra rufa eat algae, tiny animals (zooplankton and arthropods), and detritus. As you can see, they are Omnivorous.

What Do Rainbow Fish Eat in The Wild

Rainbowfish primarily feed on insect larvae, zooplankton, insects, phytoplankton, crustaceans, detritus, aquatic animals, and terrene organisms fall into the water. They aha a wide variety of food diets in the wild.

What Do Betta Fish Eat In The Wild/ What Do Siamese Fighting Fish Eat In The Wild

One of the hardiest fish is betta. They feed on almost any animal which they will be able to feast on. Betta fish wild diet includes smaller fish, insects, mosquitoes, worms, and insect larvae. That’s why they are one of the best starter fish.

Since, in the wild, food resource is usually limited, they typically have a minimal choice on diet.

What Do Guppy Fish Eat In The Wild

Wild guppy diet has a wide variety. They feed on diatoms, invertebrates, mineral particles, algal remains, insect larvae, and the food particles left by the larger fish. Guppies are Omnivorous.

What Do Wild Crayfish Eat

Crayfish are crustaceans from the freshwater, similar to the small lobsters. Also known as freshwater lobster, crawfish, mountain lobsters, and mudbugs, etc. Omnivorous crayfish are scavengers, which means they feed on dead animals and plant materials.

What Do Angelfish Eat In The Wild

Pterophyllum fish from the family Cichlidae of freshwater, aquarists know them as Angelfish, are omnivores and feed on mid-water or surface. In the wild, they eat small crustaceans and worms. Angelfish can forage in the bottom for the bottom dweller insects of the water.

What Do Archerfish Eat In The Wild

Archer Fish in the Wild

Archerfish mainly hunt at the surface level of the water for food. They are primarily carnivores. Archerfish feed on smaller fish, crustaceans, spiders, insects, insect larvae, and zooplankton in the wild.

How Often Do Fish Eat In The Wild

The majority of wild fish spend the whole day catching and hunting for their single meal for a day. If possible, they will go for the second meal. However, a proper one meal will be enough for the wild fish.

What Can I Feed Wild Fish, Or What Do You Feed Wild Fish In A Lake/Pond

In nature, wild fish feed on insects, other fish, larvae, crustaceans, and organisms. Whatever you try to feed the wild fish in the Pond or Lake, the food should be consists of 40-70 percent protein. Wild fish also need some fat and carbohydrates.

So, if you want to feed the wild fish, remember to bring foods that are consist of those. However, some people don’t encourage to provide food to the wild fish because this may cause them to become dependent on the people’s foods to arrive without foraging by themselves.

Winding Up:

Wild fish diet varies from one type of fish to another. Environment and location also play a vital role in their food habit. So, there is no uniform answer to the question – what do fish eat in the wild. But, as per their category, some are herbivores, carnivores, or omnivores; you can assume or identify their food habit or diet.

Also, freshwater and wild saltwater fish have different diets and taste for the food. However, major marine fish are predator types. They feast on each other. Others live by having plankton or other available organisms.

Occasional feeding to the wild fish is ok, but give them food with 30-70 percent protein.

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