The rudd is native throughout most of Europe, but it is not native to Ireland. Although it is an introduced species, they are considered benign as they have no significant impact on native species or ecosystems. In Ireland, they have been redistributed for angling, often to areas with smaller, isolated lakes where they have managed to escape the impact of roach: rudd thrive best in waters from which roach are absent. In Ireland, rudd can interbreed with other closely related species from the Cyprinidae family of fishes and forms hybrids with bream and, to a lesser extent, with roach.
Rudd are a beautiful golden colour, with yellow eyes, bright red pelvic and anal fins and a distinctive up-turned mouth. They prefer clean waters with plenty of aquatic vegetation and typically reside lowland lakes, still backwaters of rivers and canals, in which they form shoals that feed on invertebrates, plankton and insects, especially at the surface. They spawn in summer in shallow weedy areas.