(Abramis ballerus), a fish of the family Cyprinidae. The blue bream is up to 40 cm long and weighs up to 600 g. The body is more elongated than that of the common bream (A. brama). The blue bream inhabits large lakes and rivers in Europe east of the Rhine River. It is also present in the basins of the North, Baltic, Black, and Azov seas and in the northern part of the Caspian Sea. The fish is encountered in brackish waters of the Baltic Sea and the Sea of Azov.
The blue bream reaches sexual maturity in the fourth year of life, when it measures 18–20 cm long. The average fecundity is 11,000 eggs, and the maximum fecundity is 76,000. Spawning occurs from late April to mid-June. The sticky eggs are deposited on plants at depths of 30–40 cm. The fry hatch in about two weeks. The blue bream feeds mainly on zooplankton. It is especially common in reservoirs because of the abundance of plankton.