A small goby fish spotted near a coral in the Bay of Bengal. Gobiidae, or gobies, is one of the largest fish families with over 2,000 species. Most gobies are small in size, typically less than 10cm in length. These little fish are generally bottom-dwellers and can be found all over the world in tropical and temperate near shore-marine, brackish and freshwater environments. On coral reefs, gobies make up 35 percent of the total number of fish. They feed on small invertebrates, although some of the larger ones eat other fish, while a few feed on planktonic algae.