Gobies are an extremely diverse group of fish counting over 2,000 species. The majority of species are characterized by their cylindrical bodies. They usually have two dorsal fins, round heads with pores and pelvic fins that may be fused into a disc or cup.
Many species are found in intertidal areas along the coast. Some species are found in freshwater. Today, thousands of them are reared for the aquarium trade.
Gobies lack gas bladders, internal organs found in many bony fishes which provides natural buoyancy. As a result, gobies live on or very near the bottom. Many remain relatively small, less than four inches in length. They are easy to feed and nonaggressive.