It is native of the coast this of the Pacific Ocean, from Alaska to the north of Mexico . At the moment it is the trout more widely distributed in all the places of the world in where the waters you cold and crystalline they allow its acclimatization, as much in the North hemisphere as in the South hemisphere.
Steelhead- exists a well-known variety like trout steel head -, that migrates to the sea to grow and to feed itself and returns to the fresh water to lay eggs, like the marine salmons. In the river Santa Cruz a variety has been detected, to which the fishermen call steel Head, because displays a behavior similar to the one of the north, although by the recent investigations give in question account of a rainbow of river that with great sense of the opportunity, has developed a very particular anadromía, doing repeated migrations to the sea in search of food and returning to the rivers other so many times to lay eggs. Unlike his homónima of the north that dies in high percentage after freza and with a service life that rarely passes the three egg-layings.
The trout arcoiris distinguishes itself of the other salmónidos ones by the wide purple band that it has in each one of his flanks, from opérculo to the tail. Its back is green olive and its silverplated sides, becoming white in the belly. It presents cleared black spots in almost all the body, mainly in the back. The dorsal fins and of great volume profusely are speckled. The anal fin can display the white external edge in the trouts that frequent streams.
In the lakes there is a silverplated form, with the bluish back and without reddish stole. In this case is confused it with the locked up salmon or the brown trout of lake, that more is silverplated. Difference of first by having pedúnculo of great volume more thickness, the fin of great volume less forked and black spots in the fins. Of the second difference fundamentally to lack itself spots with ocelos (dark spots surrounded by one more a clearer aureole).
Its feeding very is varied and consists mainly of invertebrates. They reach sizes greater than the trouts of stream and in general smaller than the brown trouts. It is much more rustic and tolerant which the other introduced salmónidos ones, adapt to almost all type of atmospheres and is but the adapatable one to the young in artificial form. In the deposits varieties of greater growth have been obtained, with greater percentage of meat and that lay eggs at different times from the year.
In our country it lives in most of patagónicos atmospheres, and of his resistance to the high temperatures, she is in favor also widely distribuída in rivers of the north and center of Argentina .