The Sunbleak (Leucaspius delineatus) is a small Eastern European cyprinid that has been introduced into the UK - either as fry accompanying other imported live fish, or released illegally by aquarists. Sunbleak has other names - Belica and "Motherless Minnow" being examples
The Sunbleak is a slender silvery fish, reaching about 10 cm. It has many easily dislodged silvery scales, and a short lateral line along the first half-dozen scales of the 40-46 scales along the body length. It has an elongated anal fin (III,10-13 rays) but a small dorsal fin (III,8) The back is olive. There is a bluish or greenish-blue longitudinal stripe along each side . The tail root is a delicate orange colour. Eggs are laid on submerged vegetation by the female in spiral bands and guarded by the male fish. Lifespan is up to five years. It inhabits all sorts of still and slow-flowing fresh water.
Sunbleak are well established in many waters despite the Environmental Agency declaring them an alien fish and attempting to stop their spreading.