bluefish vs percoid fish

bluefish and percoid fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
bluefish	Yes	No	No	No
percoid fish	Yes	No	No	No

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

bluefish: bluish warm-water marine food and game fish that follow schools of small fishes into shallow waters
percoid fish: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of bluefish include percoid, percoidean.

bluefish (noun)	percoid fish (noun)
bluish warm-water marine food and game fish that follow schools of small fishes into shallow waters	any of numerous spiny-finned fishes of the order Perciformes
fatty bluish flesh of bluefish