Thymallidae

(graylings), a family of fishes of the suborder Salmonoidei. The body is usually 25–35 cm long and weighs about 450 g. Some individuals have a body length of about 50 cm and weigh as much as 1.4 kg. Graylings have a long dorsal fin with more than 17 rays.

There are five known species, distributed in foothill streams and, less commonly, in lakes of the temperate and frigid zones of the northern hemisphere. Four species occur in the USSR: the common European grayling (T. thymallus), the Kosogol grayling (T. nigrescens), the Mongolian grayling (T. brevirostris), and the arctic grayling (T. arcticus). The arctic grayling has four subspecies: the Baikal white grayling, the Amur grayling, the Kamchatka grayling, and the North American grayling.

Graylings feed on small fishes and invertebrates, mainly the aquatic larvae of insects; they sometimes eat salmon roe and fry at salmon spawning grounds. Spawning occurs in the spring; the females deposit 3,000 to 10,000 eggs on rocky bottoms. Graylings are fished locally and are artificially bred.