Rainbow trout

имя существительное [зоология] радужная форель

Большой англо-русский словарь

Rainbow trout

зоология форель радужная (Salmo irideus)

Англо-русский научно-технический словарь

Rainbow trout

noun a large stout-bodied salmonid fish (Oncorhynchus mykiss syn. Salmo gairdneri) of western North America that is related to the Pacific salmon and is typically greenish above and white on the belly with a pink, red, or lavender stripe along each side of the body and with profuse black dots — compare steelhead

Merriam-Webster's Collegiate Dictionary