trout vs food fish

trout and food fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
trout	Yes	No	No	No
food fish	Yes	No	No	No

As nouns, food fish is a hypernym of trout; that is, food fish is a word with a broader meaning than trout:

trout: any of various game and food fishes of cool fresh waters mostly smaller than typical salmons
food fish: any fish used for food by human beings

Other hypernyms of trout include salmonid.

trout (noun)	food fish (noun)
any of various game and food fishes of cool fresh waters mostly smaller than typical salmons	any fish used for food by human beings
flesh of any of several primarily freshwater game and food fishes