What Does A Small Fish Eat

What Does A Small Fish Eat?

The diets of fish that live in the ocean vary slightly from species to species. Depending on the size of the fish, the diet can range from one to three small meals a day, whereas others graze all day. A common question is, what do smaller fish eat?

If they live out in the ocean, small fish will have a balanced diet, usually consisting of even smaller sea animals such as tiny crustaceans, algae, plankton, and smaller fish. Whereas if they live at your home, they may enjoy frozen shrimps, prawns, krill, and bloodworms. 

This article will discuss what small fish eat. So keep reading! We have everything you need to know about the diet of a small fish, whether it be a pet or a fish that lives in the ocean.

What Do Small Fish Eat At Home?

If you’re interested in getting some fish for your home and you are curious as to what small fish eat when you keep them as pets, this diet can vary depending on the size of the fish. 

One of the most common forms of food for pet fish is a dry form that comes in the form of pellets and granules, which can come in a floating or sinking variety. Dry fish food will usually be a lot lower in fiber, but adding vegetables to this should reduce the chance of bloating in your little friend. 

Frozen food is another option that is relatively common among smaller fish which are kept as pets. You may opt for worms, prawns, krill, plankton, and even baby shrimps, all of which are nutritious and very beneficial to the fish’s diet. You can even get spirulina from the pet store that come conveniently frozen in cubes for any herbivores. 

You may also choose to feed your fish at home with live feed available from all pet stores. This includes live shrimp, brine, small feeder fish, crickets, and even worms. Depending on the size and species of your fish, this list will vary slightly. 

Not all fish are carnivorous, as many smaller fish prefer to feed on green food such as sea and land vegetables. If your fish are part herbivores, you can feed them a mixture of cucumbers, carrots, spinach, lettuce, zucchini, and many other vegetables. You’ll want to cut the greens into tiny bites and remove any uneaten veg after a day. 

What Do Small Fish Eat At Sea?

Fish living at sea usually have a diet that’s relatively different from those living inside of tanks and aquariums simply because they have to hunt for their own food daily. While they may not get to enjoy the frozen shrimp and krill, they will still find a way to enjoy a healthy and balanced diet. 

Most small saltwater fish will live on a diet of anything that is smaller than them. This will include zooplankton, tiny fish, fish larvae and eggs, worms, jellyfish, small crustaceans, and even floating insects. 

A large amount of the smaller fish that make up the ocean’s population will also feed on both microalgae and macroalgae. If given the chance, this includes green, red, blue, and brown algae and other plants, such as seaweed. 

Usually, the smaller fish that live in the sea, such as the clownfish, will enjoy a diet mainly made up of sea plants and tiny sea animals. They may even eat the residue that’s left behind from their anemone partners; however, for the most part, it consists of plankton. 

What Do Small Fish Eat In A River?

Fish that live in rivers, lakes, and streams usually don’t have as much of a choice regarding food when compared to their ancestors who roam free in the open ocean. However, they still manage to find enough food to enjoy a balanced diet. 

Small fish that live in rivers usually eat anything they can, such as insects, baitfish, tiny crustaceans, and other aquatic organisms. These fish will usually eat other fish, yet they are opportunistic, meaning that their diet will vary depending on what’s available. 

The herbivorous fish that make up the river’s population will survive by grazing on any kind of aquatic vegetation, which is very beneficial to the overall ecosystem as they prevent overgrowth.

Omnivorous fish or fish that enjoy a diet of both meat and plants help to control the overall animal and plant population in their ecosystem. In contrast, the predatory species of river fish are essential to keeping the populations under control. 

Do Small Fish Eat Water Fleas?

Small fish will eat just about anything they can to survive, and usually, they will take whatever they can get, whether it be various forms of algae or small species of ocean animals. But what small fish eat water fleas?

Water fleas are a small species of crustacean that live on in the ocean, collecting algae, bacteria, and detritus with their tiny legs. They are usually referred to as Daphnia and are welcomed by all smaller fish in the ocean as a tasty snack. 

When food sources are low or hard to find, smaller fish will feed on water fleas which can help keep fish reach their caloric intake for the day. If you have marine fish in your home, these are available for purchase from most pet stores and can come freeze-dried for convenience. 

Do Small Fish Eat Seaweed?

While we know that many species of fish enjoy a diet of both meat and plants, some prefer to eat plants such as algae and other sea vegetables solely. But will small fish living in the ocean eat seaweed? 

Smaller fish, primarily herbivorous fish, will indulge in seaweed from time to time. Omnivorous fish will also enjoy a snack on seaweed when they aren’t hunting other smaller prey, and many species of fish will eat seaweed as they are hunting in the ocean. 

Seaweed provides a nutritional meal for many of the ocean’s plant eaters and a safe place to live for many of the smaller fish. 


So, now you know what small fish eat in the ocean and what kind of diet is needed if you plan on keeping one of these marine fish as a pet in your home. Just be sure to look into the particular species, as this will ensure that you feed it precisely what it needs.