bluefish vs percoidean

bluefish and percoidean both are nouns.

Word	Noun	Adjective	Verb	Adverb
bluefish	Yes	No	No	No
percoidean	Yes	No	No	No

As nouns, percoidean is a hypernym of bluefish; that is, percoidean 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
percoidean: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of bluefish include percoid, percoid fish.

bluefish (noun)	percoidean (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