sergeant fish vs percoidean

sergeant fish and percoidean both are nouns.

Word	Noun	Adjective	Verb	Adverb
sergeant fish	Yes	No	No	No
percoidean	Yes	No	No	No

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

sergeant fish: large dark-striped tropical food and game fish related to remoras; found worldwide in coastal to open waters
percoidean: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of sergeant fish include percoid, percoid fish.

sergeant fish (noun)	percoidean (noun)
large dark-striped tropical food and game fish related to remoras; found worldwide in coastal to open waters	any of numerous spiny-finned fishes of the order Perciformes