Rainbow Trout is a member of the salmon family that comes from the western parts of the USA. It was introduced to Europe in the 1890s and has thrived in some trout waters up to the present day. It is stocked in streams and small rivers, in reservoirs and cold ponds. It spawns mainly in the winter months, but few populations are self-maintaining in Britain. This fish grows very fast where there is plenty of food and sometimes reaches a weight of 1 kg as early as its third year of life. In Europe it can exceed a length of 50 cm and weighs between 4 and 5 kg.
It has a bluish or olive-green back and silvery sides with a wide pink or red lateral stripe. The sides, back, dorsal and caudal fins are densely covered with dark spots. Young rainbow trout feed on a range of invertebrates, especially insects both larval and adult, whilst older specimens prey continuously on other fish. North America as well as Europe is inhabited by non-migratory populations, which live permanently in freshwater. In contrast, other populations of the rainbow trout, called steelheads, have left freshwaters for the sea and only return to the rivers to spawn.
Maximum size and weight: 60 cm, 5 kg. Identifying characteristics: Lateral pink or red stripe along silvery sides. Sides, back, dorsal and caudal fins densely
Other related species: Salmo trutta or Brown Trout