What Do Fish Eat?

feed aquarium fish

Unlike people, fish don’t really have an option when it comes to what they eat.

They don’t get to go to a buffet and pick out some meat, a little salad, and a taco.

No, fish don’t have much of a choice in what they eat. And, different types of fish eat different types of food. Some fish are carnivores, craving the meat of other animals and fish.

Others are herbivores, preferring to eat algae and plants. It all comes down to what kind of fish we’re looking at and where they live.

The other thing that impacts what a fish eats is where they live. If a fish is in the wild, their diet is going to be quite different from their diet living in a fish tank. Different foods are available to them in these different ecosystems.

The goal is to make sure you provide your pet fish with the same kinds of foods they would eat if they were in the wild. This way, they’ll not only live a nice, long life but they’ll also enjoy their food.

Here, we’ll talk about the basic types of foods fish eat. Of course, we can’t talk about every kind of fish or we’d be here for a week!

But we’ll cover the basics. This way, you can satisfy your natural curiosity and get an idea of whether you’d be a good chef for your pet fish.

Three Types of Eaters: Carnivores, Herbivores, and Omnivores

This is where we make you feel like you’re sitting in fifth grade science class. We’re going to go over the 3 main types of eaters. This is important because, when you buy your pet fish, they’re going to let you know what kind of diet they keep.

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If you don’t know what an omnivore is, you’re going to have a hard time figuring out what to feed your fish.

The 3 main types of fish are carnivores, herbivores and omnivores. Let’s talk a bit about each type.


These types of fish eat meat – they like to eat meat whether it’s dead or alive. This includes small animals and other fish. Some of the common fish that are carnivores include:

  • Piranhas
  • Killfish
  • Bettas
  • Pipefish

Carnivore fish tend to have much bigger mouths and sharp teeth. This lets them tear into the meatier foods. They are typically good hunters and actually enjoy hunting their prey. While all fish need some protein to survive, carnivores prefer about 75% of their diet to be from meat. 

If you have carnivore fish in your aquarium, you can feed them frozen meats such as shrimp and clams. They also eat insects and worms – these are a lot less expensive than frozen shrimp. They don’t like carbohydrates so stay away from them. They can’t digest them so it can give them a tummy ache!

fish food


If you recall from your days in elementary school, herbivores eat plants and vegetables. They do not like meat. Yes, they still need some form of protein in order to survive. Some of the fish that are herbivores include:

  • Parrotfish
  • Surgeonfish

It’s interesting. We pointed out that carnivores need larger and stronger teeth to break into the meat. Likewise, herbivores need a stronger digestive system to digest things like plants and veggies. 

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Herbivore fish don’t have a stomach. They use their intestines to break down their food. This means you have to feed them more often than other types of fish. Some of the things herbivores like to eat includes:

  • Fruit
  • Algae
  • Plants
  • Vegetables

Just keep in mind – these fish will eat a lot of what’s already in the tank. But you still need to feed them often and make sure they get some protein. You can buy fish flakes from the pet store if you’re not sure what kind of protein to give them.


You probably already guessed, but omnivores have the best of both worlds. They eat both meat and plenty of vegetables, plants and fruits. Some of the fish that fall into this category include:

  • Batfish
  • Goldfish
  • Catfish

These fish have a digestive system that is a bit like both carnivores and herbivores. This means they can break down both types of foods quite easily. One of the suggestions we make is that new pet owners stick to omnivore fish. They’re really easy to take care of and they’ll eat just about anything. You don’t have to be so careful with what you feed them.

aquarium fish eat

Is it Okay to Buy Prepared Fish Food?

For a lot of fish parents, it seems easier to just buy fish flakes at the pet store. This way, you know that your fish are going to get all the nutrients they need. It’s also a lot easier, cheaper and more convenient. But, remember – you have a pet. Your fish rely on you for their food. You need to make a real effort to give them the best possible nutrition. 

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Here are some tips when it comes to buying your fish pellets or flakes:

  • Always look at the ingredients. There should be as few carbohydrates as possible.
  • Check for filler foods. You want to make sure the nutritious content is high.
  • Flakes are good for fish that stay at the top of your tank. Pellets or discs are better for bottom-feeders.
  • Some of the good ingredients to look for are fish meal, shrimp meal, earthworms, spirulina, and squid meal.

How Often Should You Feed Your Fish?

One of the first questions new pet owners ask is how often they should feed their fish. The answer is – it depends. You really want to ask the pet store when you buy your fish. They’ll give you some instructions. You can also come online and read the information on how much to feed your fish.

The general rule is that it’s better to feed your fish too little than too much. Some of the dangers of overfeeding your fish include:

  • fin rot
  • Fatty liver
  • Low oxygen levels
  • Flatworms
  • Clogged filters