rainbow perch vs surf fish

rainbow perch and surf fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
rainbow perch	Yes	No	No	No
surf fish	Yes	No	No	No

As nouns, surf fish is a hypernym of rainbow perch; that is, surf fish is a word with a broader meaning than rainbow perch:

rainbow perch: Pacific coast fish
surf fish: small to medium-sized shallow-water fishes of the Pacific coast of North America

Other hypernyms of rainbow perch include surffish, surfperch.

rainbow perch (noun)	surf fish (noun)
Pacific coast fish	small to medium-sized shallow-water fishes of the Pacific coast of North America
	a fish of the Pacific coast of North America