spadefish vs percoidean

spadefish and percoidean both are nouns.

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

As nouns, percoidean is a hypernym of spadefish; that is, percoidean is a word with a broader meaning than spadefish:

spadefish: deep-bodied disk-shaped food fish of warmer western Atlantic coastal waters
percoidean: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of spadefish include percoid, percoid fish.

spadefish (noun)	percoidean (noun)
deep-bodied disk-shaped food fish of warmer western Atlantic coastal waters	any of numerous spiny-finned fishes of the order Perciformes