Trout
Salmo trutta
Length 50-80cm, often much smaller

A familiar and popular sport fish. Widespread and often common both in fast-flowing, unpolluted rivers and streams, and in stream-fed lakes. Known in two forms: brown trout which spends entire life in freshwater and sea trout which only ventures up rivers to breed. Both forms spawn in shallow water on gravel beds. Young spend first year or so in nursery stream before moving downstream to larger river (brown trout) or to sea (sea trout). Feeds mainly on invertebrates.