Rainbow trout 

(Oncorhyncus mykiss)

This fish fills a similar niche to the Brown trout (Salmo trutta), also having migratory and non-migratory forms

for more detailed info on the normal form follow arrow http://www.adfg.state.ak.us/pubs/notebook/fish/rainbow.php

for more detailed info on the anadromous steelhead follow arrow http://www.adfg.state.ak.us/pubs/notebook/fish/steelhd.php

picture from Dept of Fisheries and Oceans