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What Do Fish Eat?

Before going out to sea to fish for your dinner, have you ever wondered what your fish might have had for their dinner?

shark jumping out of the water

Fish at sea and the fish in your tank might have the same dietary needs, but how they get it is drastically different. Keep reading to find out what fish eat and how they get it.

What Do Wild Fish Eat?

Just like people, fish need to eat a healthy combination of fats, proteins, vitamins and minerals in their diet. Similar to how fishermen have to work for their fish, fish have to work hard to catch their own meal oftentimes.

mahi mahi swimming

It is important that fish eat the correct type of food for their species and size, which includes anything from plants to other fish or both. Their diet can be also be impacted by their surrounding ecosystem depending on what resources they have available to them.

Fish, just like humans, can be picky eaters too. There are fish that strictly stick to a plant-based diet whereas other fish, such as Red-Bellied Piranhas, prefer to eat other types of fish.

What Do Fish Eat in the Ocean?

Bodies of saltwater contain many different types of fish. Much like other types of animals, different fish have different dietary preferences. Carnivorous saltwater fish primarily eat mysis shrimp, bloodworms and brine shrimp.

barracuda swimming in the water

While oceans provide ample food for enormous fish, such as sharks, small fish must also figure out a way to survive in a place with so much competition.

Small fish often solve this problem by finding parasites and other various sea creatures on other fish. They then proceed to eat them off of each other. This is beneficial to both parties because the fish both satisfy their hunger and clean off their friend. 

What Do Freshwater Fish Eat?

Freshwater Fish reside in rivers, lakes and wetlands. These fish are some of them most common fish to be caught, including Trout, Catfish and Salmon.

largemouth bass jumping out of the water

Live food such as earthworms and water fleas are some of the most popular foods that freshwater fish consume. Small and newly hatched fish eat microorganisms along with micro worms and other small fish eggs.

Are Fish Omnivores?

The answer to this question is both yes and no. Fish can be omnivores, but they can also be herbivores and carnivores.

school of mullet swimming

Herbivore Fish

Herbivorous fish are fish that primarily eat algae and plants along with vegetable matter and fruits they might find in their body of water.

Colorful Parrot Fish

Herbivorous fish can be found in both freshwater and saltwater with plenty of food options to eat. Some examples of herbivorous fish include Bovines, Camelids and Carnivora.

Carnivore Fish

Carnivorous fish eat other fish and meat in in the ocean. Rather than chewing on their meat, carnivorous fish they are able to tear parts of their prey up and swallow them whole.

bluefin tuna

Examples of carnivorous fish include Piranhas, Sea Basses and Tuna Fish. That’s why using live bait for tuna is such a common method used by fishermen.

While a carnivorous fish might eat plants, the plants provide no nutritional value to them. Instead, their digestive track is developed to handle large pieces of meat and have room for a whole fish in their stomach.

Typically in the wild these fish will feed on other smaller fish, insects such as blood worms, and larva.

Omnivore Fish

Omnivore fish get the best of both worlds. Omnivore fish eat both plants and other meat in the ocean.

can you eat carp

Their digestive track allows both vegetable matter and meat to travel through unlike herbivorous and carnivorous fishes digestive tracks. Different types of omnivorous fish include Freshwater Fish, Freshwater angelfish and Barb.

Food for Pet Fish

From ocean to indoor tank, there are a lot of fish in the wild that would make a good pet fish to spruce up your aquarium.

a fish tank on a shelf

A fish’s diet can be very unique,e so it is important to know how to satisfy your new fish’s dietary needs before purchasing.

Accommodations can be made for all types of herbivorous, carnivorous and omnivorous fish in the tank.

When adding to your community of fish in your tank take into consideration the history of the fish and if it will get along with other fish. You do not want your carnivorous fish to eat the entirety of your tank.

Pellets vs Flakes

There are about four different kinds of dry food that include flakes, pellets, granules and discs.

person holding a handful of fish feed

Flakes and pellets are the most common types of dry food, but there are key differences between them. There are different types of food that are made to be more suitable for some fish than others.

Flakes are better to give pet fish that come to the top of the water to eat. Bigger pellets and discs however are better for bottom feeders as they sink to the ground when put in water.

a pile of fish flakes

With dry food such as pellets, it is easier to overfeed your pet fish. Overfeeding fish is very important to avoid to ensure a long life for the fish. This is easy to avoid by following directions in the packaging of how much and often to feed based on the type and size of fish.

Frozen food

When pellets and flakes are not enough for your fish, you have the option to feed them frozen food.

frozen worms in a container for  fish food

Frozen food for fish includes worms and insects, and is available to purchase in pet stores. This type of food is less common for pet fish but is necessary for carnivorous fish.

Frozen food provides protein for fish who do not receive a sufficient amount from the pellets and flakes and might be necessary in addition to the dry food.

A precaution one should take when giving this to pet fish however is the risk of disease that can be carried through the worm or insect. 

Final Thoughts

There are so many different species of fish in the waters of the world that there’s no short answer to the question of “what do fish eat?”.

Hopefully, this guide has answered all your questions about what all the different types of fish out there are eating. It’s quite fascinating!

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