bigeye vs percoidean

bigeye and percoidean both are nouns.

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

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

bigeye: red fishes of American coastal tropical waters having very large eyes and rough scales
percoidean: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of bigeye include percoid, percoid fish.

bigeye (noun)	percoidean (noun)
red fishes of American coastal tropical waters having very large eyes and rough scales	any of numerous spiny-finned fishes of the order Perciformes