The Ruffe is a member of the Percidae family. It is widespread in fresh water and brackish water bodies of Europe, the western limit of its native range is France. In the east it extends up to the Kolyma. Ruffe do not occur in Italy, Spain and Greece, nor in the South Caucasus. It lives in river bays, lakes, reservoirs and ponds with flowing water and a soft bottom with no aquatic plants. It avoids strong currents, preferring quiet bays and pools with whirling water. The ruffe doesn’t like sunlight and warm water, therefore it is most active in the time of twilight and at night as well as in cloudy weather. Ruffe lives in shoals. It is a very voracious species, it feeds at any time, being a typical bentophagous fish. Its diet is based on bottom water invertebrates (worms, mollusks, crustaceans, insect larvae), fish roe and larvae. Ruffe’s body is short, flattened along flanks and covered with dense scaling. The mouth is small, there are tiny orderly teeth on its jaws. The back is grayish green with black spots, the flanks are yellowish, the abdomen is whitish. Dorsal and caudal fins have black spots on them. Fins and opercula are equipped with sharp spikes. Its coloration depends on its habitat: in water bodies with a sandy ground ruffe are lighter than in those with a silted bottom. Ruffe’s average length is from about 8 to 12 cm, its ranges from 15 to 25 g. Large specimens reach a size of about 20 cm and a weight up to 200 g.