In the wild, gobies serve as important prey for large marine predators. They are also increasingly popular in captivity due to their nonaggressive disposition and unique anatomy. Gobies are generally small and frequently brightly colored. They also have a sucker along their abdomen that allows them to attach to plants and aquarium glass. Most gobies are carnivores and subsist on a diet of small fish and plankton.
In the wild, gobies thrive on a diet of mussels. Gobies have molar teeth that allow them to crush shells, and they especially enjoy zebra mussels.
Some species of gobies are bottom dwellers who live on or near coral reefs. These fish feed on coral in addition to tiny plants and animals that live near coral. Their molars help them to crush the coral and extract beneficial calcium and other minerals.
Plankton are tiny floating organisms that include a variety of species. Plankton may include jellyfish, cyanobacteria, eggs and larvae of larger animals and protozoans. Gobies feed on a variety of plankton and a few species feed solely on planktonic algae.
Few captive gobies have the opportunity to feed on mussels or coral, but captive diets can still be nutritionally complete. Blood worms, which can be purchased at many pet stores, are an excellent staple food. Most fish food companies make specialized goby flakes that include small pieces of many things gobies eat in the wild. Gobies also enjoy fish eggs, which can be purchased at some farmer's markets. Shrimp pellets are also good additions to a goby's diet. Be sure to purchase shrimp pellets that sink, since gobies are bottom dwellers.