Roach are easily identified by their silver colour, red fins and red eyes. Roach readily hybridise with bream and rudd and these hybrids are common in areas where the species co-exist. Because of the prolific nature of roach, they can over run a mixed fishery in a relatively short time period. Egg sizes is 1-1.5 mm. Adult roach feed mainly on insects, crustaceans.
Juveniles feed on zooplankton and phytoplanton.
They have a dark olive or blackish colour. The fins are rounded and the tail is almost unforked. It is possible to distinguish the sexes based on the shape of the pelvic fins on the underside of the body. Male fish have very large spoon-shaped fins, while those of the female are longer, more pointed and triangular in shape. Spawning therefore is normally restricted to late June and July.