The common bream is native to Western and Central Europe into Russia, but it is not native to Ireland. They are believed to have been introduced to Ireland during the Middle Ages to farm as food in fishponds at monastic settlements. Bream are a relatively large fish, growing to over 5kg in weight, and gather in shoals, making them an important species for coarse anglers. They may be found in lakes, canals and large slow-flowing rivers, and their distribution in Ireland is more widespread through relatively nutrient enriched waters.
Bream have black fins and deep, laterally compressed bodies that are a silvery colour in young bream, which are known as skimmers, but that turn a deep bronze colour in older fish, which are known as slabs or bronze bream. Bream are long-lived, and individuals over 20 years of age have been recorded in Ireland. Bream use their downwards facing, protruding mouth to feed on invertebrates living in shallow areas on the bottom of rivers and lakes. This bottom-feeding behaviour of bream can disturb sediment and make the water dirty or turbid, thereby having an impact on aquatic plants and other animals that live in habitat where they are present.
Bream feed most actively and spawn during the summer months when water temperatures reach about 15°C, and they frequently migrate up to 40km from their home ranges to spawning grounds. At spawning time, male bream develop small white spots called tubercles all over their heads. In Ireland, bream can interbreed with other closely related species from the Cyprinidae family of fishes and forms hybrids with roach and, occasionally, with rudd. The numbers of bream have declined where roach occur, due to competition with roach in spawning areas and proliferation of viable hybrids that now outnumber the parental bream populations.