Sheatfish (Silurus glanis; Ukrainian: som zvychainyi). A large, scaleless, freshwater catfish of the family Siluridae, reaching 5 m in length and up to 300 kg in weight. It is a valuable commercial fish. In Ukraine sheatfish inhabit the Black Sea basin. In Western Ukraine a pygmy sheatfish of a different family (Amiurus nebulosus) has been acclimatized; its body length is about 30 cm, and its weight, 500 g.