The carp measures between 25 and 51 centimetres. It has a hump-backed body and its head is about a quarter of its body length, with quite a small mouth. The dorsal fin is long, with a strong, lightly serrated third spine; the anal fin is short with six to eight branched rays and a strong, lightly serrated spine. Its colour varies from olive green to reddish brown on the back. Paler fish feature a brassy tint with a rounded dark spot near the base of the tail. The pectoral, pelvic and anal fins are a bright reddish bronze.
The crucian carp can be found throughout Europe.
The crucian carp lives in still waters or, less commonly, slow-flowing rivers in the lowlands. It is very tolerant of low-oxygen conditions and lives in marshes with only occasional pools of open water, and in small ponds. It makes an attractive aquarium fish and quickly becomes tame. It feeds on small invertebrates and water plants.