What Do Fish Eat?

Finding one specific type of food that is suitable for all fish is hard and almost impossible. Your local pet shop may have a type of food they recommend as one size fits all to make a sale. Since different fish have different biology, their eating habits will vary depending on their species and natural habitat.

What fish eat depends on their habitat. For fish in the wild, they eat leeches, algae, crustaceans, and smaller fish. For aquarium fish, any combination of food that is a balanced diet is recommended.

Learning about fish species is a great way to know what specific species of fish prefer to eat. Some fish are carnivorous (they eat meat), others herbivores(vegetarian), and others omnivores (eating both meat and plants). In this post, we will have an in-depth look at what different species of fish eat. We’ll cover those in the ocean and also what you can feed your fish in an aquarium or pond. Please stick with us to the end!

What Do Fish Eat In The Wild?

The diet of fish in the ocean, rivers, or lakes is largely dependent on the fish species. Some species are carnivorous and eat meat from worms and small sea creatures. Others are predators and eat other small fish, while others eat vegetation.

Here’s A Summary Of What Each Category Of Fish Eats To Help You Have A Better Understanding.

Fish categoryExamples of Species What they eat 
CarnivoresCichlids, Piranhas, pipefish, killifish, tetras, bettas and arowanasLive fish, crustaceans, larvae, and insects
Herbivores Surgeonfish, parrotfish, angelfish, and butterflyfishVegetation, algae, and water plants
OmnivoresBatfish, catfish, and opaleyesA combination of meat and vegetation. 
Predators Walleye, salmon, musky, perch, and pikePrey on other fish and animals


Carnivorous fish are meat eaters and mostly eat live foods. Their mouth is large and adapted for their feeding habit of having sharp pointed teeth. They can easily grasp and tear off chunks of flesh from their prey. Carnivores have a large stomach and a short intestinal tract that cannot digest plant or vegetable matter. Carnivorous species of fish also eat worms, insects, larvae, and crustaceans. Some examples of carnivorous fish species are: Cichlids, Piranhas, pipefish, killifish, tetras, bettas and arowanas


Very few fish species in the world are herbivorous. Herbivores only eat plants, algae, and vegetable matter found on the ocean floor. Herbivorous fish have no true stomach, but they have a specialized intestine that breaks down plant matter. These fish must frequently eat because they don’t have stomachs to hold large volumes of food. They have flat teeth that enable them to grind food before swallowing. The most common herbivorous fish species are Surgeonfish, parrotfish, angelfish, and butterflyfish.


Omnivorous fish mostly eat various vegetable matter and meat: the teeth and digestive tract of these fish possess’ characteristics of both herbivores and carnivores. Omnivorous fish will mostly eat anything but get most of their nutrients from meat since it is easily digestible. Some of the most popular species of omnivorous fish are: Batfish, catfish, and opaleyes


Predators are carnivorous fish that prefer to hunt and eat other fish species. Most predators don’t eat dead meat or worms but prefer to hunt they feed. These fish switch between types of prey depending on their abundance. Predator fish can easily become pests if introduced into an ecosystem as the new top predator. A good example is the snakehead fish that has caused trouble in Florida and Maryland. Examples of predator fish are Walleye, salmon, musky, perch, and pike.

What Do Fish Eat In An Aquarium?

What Do Fish Eat In An Aquarium

Are you wondering what fish like to eat? Do you have an aquarium and want to keep your fish healthy? If yes, you are in the right place. Feeding your pet fish can be quite confusing for a novice. The fish food section at a pet store can add to your confusion and be overwhelming, but you don’t need to worry.

Before buying food for your pet fish, you need to learn about their species. Find out if they are carnivores, omnivores or herbivores. The best type of fish for a fish tank is omnivores. Carnivorous fish tend to attack each other, while herbivores require constant feeding making them unsuitable for aquariums. Once you determine what species you have, you can easily choose what to feed them from various options.

You have many options to choose from that provide proper nutrition to your fish and ensure they are healthy. The options include:

1. Dry Foods: These come in granules, pellets, or flakes that float or sink. Dry foods also have options for specific species of fish. Dry food is low in fiber and should be supplemented with vegetables to prevent swim bladder disorders or bloating. Most pet stores also sell nori algae or dry spirulina sheets, which are great for herbivorous fish to munch on.

2. Frozen Food: most fish enjoy frozen food items such as shrimps, prawns, planktons, bloodworms, mussels, and krill. For herbivores, frozen spirulina cubes are available at pet stores.

3. Live Food: if you have large carnivorous fish, you will find that most prefer live food such as feeder fish. Other live food options include worms, crickets, ghost shrimp, or live brine.

4. Greens: sometimes, fish will much on aquarium plants when they need vegetables. Ensure you give them fresh greens and clip them on the inside of the tank. Some of the options you can give include lettuce, courgettes, spinach, and cucumbers. You can keep rotating the greens after every 24 hours to ensure fish eat a variety of fresh vegetables.

5. Freeze-Dried: you can find Mysis shrimp or tubifex worms as freeze-dried cubes at pet stores. These are nutritious and ideal for carnivorous fish.

Different fish species will need different foods; if you have a combination of fish in your aquarium, use a combination of food. You can use both sinking and floating foods with different nutritional content to ensure they obtain the nutrients they need.

How Much Should I Feed My Fish?

How Much Should I Feed My Fish

Overfeeding fish is more common to pet owners than underfeeding them. Overfeeding can affect the water quality and, in turn, the health of your fish. Overfed fish excrete more waste, and leftover food starts to rot in your tank. In some instances, overfeeding may cause fin rot, fatty liver, low oxygen levels, and clogged filters. Signs of overfed fish include a polluted tank, increased levels of nitrates or nitrites, and ammonia. Now that you know the hazard of overfeeding, it is best to stay safe by avoiding it. 

How do you know the right amount of food to give? Some people tend to feed fish according to the size of the aquarium, which is wrong. The number of fish in the aquarium will determine how much feed they need. Ten fish in a huge aquarium need the same amount of food as ten fish in a small aquarium.

If you have adult fish in your aquarium, we recommend feeding them once a day at around the same time every day. You can opt to give small amounts of food multiple times a day too. Young fish may need up to four feedings each day. For herbivorous species, we recommend giving live greens that they can snack on throughout the day. This is because they have small stomachs and cannot hold large amounts of food. 

When feeding fish, the rule of thumb is to give only what they can eat in five minutes. If anything is left after that time, you are probably overfeeding. In the case of overfeeding, promptly remove uneaten food using a net or siphon. We recommend putting food in the aquarium in the evening before switching off the light for them to eat overnight for nocturnal fish. 


As we’ve discussed, the eating habits of fish vary depending on their species and habitat. Fish in their natural habitat will find what is most suitable and nutritious for them. For fish in an aquarium, you have to feed them with a balanced diet according to their species. Ensure you study your fish and what they love to avoid overfeeding them.

As part of a great feeding routine, store your fish food properly. We recommend storing your fish in a cool place to maintain their vitamin value and ensure they get maximum nutritional benefits from the feed. Buying small amounts instead of buying in bulk also helps ensure they don’t lose their nutritional value. The type of feed you give to your fish is as important as the amount. Research about the species you have to determine the most appropriate feed. Some fish food is specific to certain species, while some are designed for saltwater fish and others for freshwater fish. Always read the label before you buy.

Whatever your feed choice is, ensure it provides minerals, vitamins, and proteins that your fish need. Small amounts of nutritional feed are better than lots of cheap food so choose wisely. we hope this post helps you understand fish patterns and choose the best feed for your pet fish.

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