The Tench is a fish of the cyprinid family. It is widespread in Europe (except the basins of the Norwegian Sea, the White Sea and the Barents Sea). In Siberia, it occurs in the middle course of the Ob and the Yenisey. Tench is rather undemanding towards the quality of water and may be artificially bred in ponds. It likes still water overgrown with reed and is rather warmth-loving. Usually it prefers quiet river backwaters, silted lakes and ponds. The tench is a slow and sluggish fish. It leads a sedentary lifestyle. It stays in the bottom water and avoids sunlight. The tench feeds on bottom water invertebrates (insect larvae, worms, mollusks), extracting them from silt at 7-9 cm depth. Full-grown fish, beside living creatures, it feeds on underwater plants and detritus. The mouth of tench is very small, on each side of it there is one short barbel. Its pharyngeal teeth form one row, they are elongated and hook-shaped. The fins are rounded in shape and gray in color. The coloration of tench depends on water color, the back is normally dark green, sometimes almost black, the flanks are olive with gold shimmering. In rivers and clean lakes, tench is always lighter and yellower. Its average body length ranges from 20 to 40 cm. A large tench may reach a length of 70 cm and a weight exceeding 7 kg.