(Leuciscus idus), also golden eye, a fish of the family Cyprinidae. The body length is up to 70 cm, and the weight, up to 2.5 kg (rarely 6–8 kg). The back is dark, and the underpart, silvery; all the fins are reddish. The ide is distributed in Europe, inhabiting rivers, lakes, and reservoirs; it is also found in the brackish waters of the gulfs of Bothnia and Finland. It attains sexual maturity in the third to fifth year of life. It spawns in April or May in shallows. The fertility is about 114,000 eggs. The ide feeds on insects, mollusks, worms, and algae. It is an object of both commercial and sport fishing. A domesticated form of ide, the orfe, is bred on fish farms.