The sunbleak (Leucaspius delineates) is an invasive non-native species from Central and Eastern Europe. It occurs in the UK mainly in southern England and probably found its way here through the aquatic trade, with fish then escaping or being illegally introduced into the wild.
It inhabits weedy water bodies and will colonise rivers, ponds and canals. The sunbleak reproduces rapidly and out-competes native fish such as roach and rudd. It feeds on tiny zooplankton and flies taken at the surface of the water.
Appearance: streamlined in shape and bright silver in colouration, with a white belly. The mouth is distinctive in that it is upturned and has a protruding lower jaw. Eyes are large in proportion to its head and it has a large deeply forked tail.
Typical size: 5-8cm
Lateral line scale count: an incomplete lateral line extending only over the first 2 to 13 scales. The scale count along the body of the fish is 40 to 46 scales.
Lifespan: up to 5 years