Trout and salmon are layman's terms.

Steelhead, cutthroat, chinook, coho, chums, sockeyes, and pinks all belong to the same Genus, 'Oncorhynchus'.

Brookies, Dollies, Bull trout, lake trout and char belong to the Genus 'Salvelinus' .

Brown "trout" and Atlantic "salmon" belong to the Genus 'Salmo'.

So basically, asking whether they're a trout or salmon is a bogus question. They're Oncorhynchus Mykiss..........and that's the only accurate way to describe it.
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She was standin' alone over by the juke box, like she'd something to sell.
I said "baby, what's the goin' price?" She told me to go to hell.

Bon Scott - Shot Down in Flames