The gobies (lat. Gobiidae) are a family of ray-finned fishes in the order Gobiiformes. More than 200 genera, more than 1600 species (black-footed goby, March goby, round-headed goby, gudgeon, etc.). Marine brackish and freshwater fishes of the coastal zone. They live in tropical and temperate waters. They range in size from 10 mm to 35 cm. The pelvic fins are fused and modified into a suction funnel. Sitting, bottom dwelling fish with a short life cycle. They lay their eggs on the bottom in nests under rocks. They feed on benthic organisms, sometimes fish.

The goby is a benthic coastal fish. The body is covered with cycloid or ctenoid scales, some species lack scales. They have a large, broad head, large, closely spaced eyes, two dorsal fins (one usually with a rigid ray) and a sucker formed by the fusion of the pelvic fins. They use this sucker to cling to benthic rocks and are held fairly securely, even in a rough storm. There are 31 species of goby in the Black Sea.

Externally, gobies are very similar and difficult to distinguish. The main differences between gobies are the number of rays on the fins, colouration, spots and stripes on the body, shading, size and number of scales. All gobies can be divided into two main groups: brackish and marine. Brackish gobies are relics and have lived in the Black Sea since it was connected to the Caspian Sea. The marine gobies gradually migrate from the Mediterranean to the Black Sea. One of the first gobies to enter the Black Sea was the green goby, which has become the only commercially important species in the marine goby group. Brackish gobies, or Pontic relict gobies as they are also called, are ideally adapted to life in estuaries. They can easily tolerate wide fluctuations in salinity from freshwater to pure seawater. For example, sand lance and sand lance are at home not only in the Black Sea, but also in the Dniester and Dnieper rivers. The Mediterranean goby, on the other hand, cannot tolerate freshwater at all and usually lives in waters with a high salt content.