White-eye bream or sapa (lat. Ballerus sapa) is a fish species of the family Cyprinidae. It is widespread in many large rivers in Europe and Asia in drainages of the Black Sea, Caspian Sea, and Aral Sea. It was introduced to several rivers in northern Russia, in Rhine and invasive in Vistula drainage, coming from the Black Sea basin through the Dnieper–Bug Canal where it is presently spreading from warmer upper reaches northward.
White-eye bream occurs in fast flowing rivers. Eastern, brackish populations enter the lower reach of rivers for spawning. Inhabit large lowland rivers and estuaries. White-eye bream (sapa) is active at night. Prey on benthic invertebrates. Semi-anadromous populations forage in large brackish-water habitats in estuaries around Black Sea.
White-eye bream spawn in large aggregations in fast-flowing water on gravel bottom or submerged vegetation. Semi-anadromous individuals begin spawning migration in November. Sticky eggs attach themselves to stones or plants.
White-eye bream is freshwater fish, common length is 15 cm but can reach up to 35 cm long. White-eye bream is usually rare and threatened due to water pollution.