steelhead is genetically a rainbow trout - which goes to sea . . . but is not a salmon.
its wild / sea diet gives it (a deeper red than) salmon coloration and it is a most tasty dish.
due to fishing pressure, last I heard only Canadian native peoples may harvest steelhead from the wild - the rest of it is farmed.
as to run of the mill farmed salmon - it's pretty bad.
our fish monger usually has Scottish farm salmon - big ones - fresh, never frozen, and it is seriously superior to supermarket salmon.
edit: the pix reminded me - arctic char is also a super option in that "taste family"