sergeant fish vs percoid

sergeant fish and percoid both are nouns.

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

As nouns, percoid is a hypernym of sergeant fish; that is, percoid 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
percoid: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of sergeant fish include percoid fish, percoidean.

sergeant fish (noun)	percoid (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