What is the scientific name of the rainbow trout, a freshwater salmonid native to the Pacific Rim?

The scientific name of the rainbow trout is Oncorhynchus mykiss.

Rainbow trout belong to the salmon family, Salmonidae, and are native to waters draining into the Pacific Ocean in Asia and North America. The species was originally described under a different name, but Oncorhynchus mykiss is now the accepted scientific name.

The name covers several forms, including freshwater rainbow trout and the ocean-migrating steelhead. Steelhead are not a separate species; they are the anadromous form of the same species. Rainbow trout have been introduced widely for sport fishing and aquaculture, so populations now occur on every continent except Antarctica.

A common mix-up is confusing rainbow trout with the Atlantic salmon, Salmo salar, or the brook trout, Salvelinus fontinalis. Their scientific names place them in different genera, even though all three are salmonids.