What Do Fish Eat?

Fish feeding habits are specific to what kind of fish they are and where they live. 

Fish can be carnivorous, herbivorous, and omnivorous... this means some of them ingest meat, plants, or both.

Algae are consumed by fish that only eat plants and those that will eat anything.  Sea grass and algae are also eaten by fish that are herbivores. Detritus, an accumulation of dead organisms, coral slime, and fecal matter, is also part of the diet of many fishes.

Some omnivorous fish, on the other hand, have a diet consisting mostly of sponges.

Closer to the sea floor, you will find crustacean feeders. The biggest part of their diet is crabs and shrimps.

Bottom feeders are omnivorous, and will eat almost anything they find. This includes worms, crustaceans, and small fish.

Other invertebrate feeders enjoy snails, shrimp, crabs, clams, and starfish. In the open water, plankton is found floating and is enjoyed by plankton feeders. It includes amphipods, shrimp, fish, and fish larvae. Fish feeders are also called ambush feeders, because they either wait till their prey comes close by, or lure them closer.

Lastly, parasite pickers are just that. They eat parasites found on other fish. Freshwater fish, too, have a varied diet. They will eat bugs that land on the water and also eat insect larvae that are under the water. They also like worms, small fish and frogs, aquatic plants, crayfish, and minnows.  

Bon Appetit

Some kinds of fish are more specific in what they each and how they feed:

• Sharks will eat anything, including fish, other sharks, plankton, and seals.
• Salmon are carnivorous, eating small fish, krill, and plankton to name a few.
• Scorpion fish like to eat small fish and do so by waiting to ambush them. They are masters of disguise and some can even change color to help them hide.
• The omnivorous goldfish eats everything from insects to detritus.  This includes worms and plants.
• Koi fish enjoy a varied diet. They like fruit, vegetables, algae, and crustaceans. 

Fascinating Fishy Facts

Here are a few fascinating fishy facts to keep you busy:

• The largest fish is the whale shark. It can grow to over fifty feet and weigh several tons. The smallest fish is the tiny goby. It lives in lakes in the Philippines, and rarely gets longer than 1½ inches.
• Scientists, in 1960, discovered a fish swimming 35,800 feet deep in the ocean. The fish looks like a sole and was about a foot in length.  
• An anadromous fish is born in fresh water, lives most of its life in saltwater, then returns to fresh water to reproduce. A catadromous fish does the opposite. It starts life in salt water, spends most of its life in fresh water, then returns to salt water to spawn.

• Not all fish swim in a horizontal position. One exception is the sea horse, and another is the shrimp fish which live in the Indian Ocean. Some deep sea fish swim and rest vertically.  
• The electric eel will discharge, on the average, 350 volts of electricity, although voltage up to 650 has been measured. Some eels are 10 feet in length.
• The most common fish in the world is the any of the species of Cyclothone. They are sometimes called “bristle mouth” and live at depths of 500 feet or deeper. They are as small as a minnow.

Under the Sea

There are thousands of species of fish in the world. Fish are cold-blooded and usually covered in scales. They have two pairs of fins, and most are oviparous, which means eggs are fertilized and develop outside of the female’s body. 

Fish “breathe” with gills. Water is taken in their mouth and pushed over the gills, where oxygen is exchanged for carbon dioxide.

The variety of fish is large, and the foods eaten by fish are an even larger variety.