sea chub vs percoid fish

sea chub and percoid fish both are nouns.

Word	Noun	Adjective	Verb	Adverb
sea chub	Yes	No	No	No
percoid fish	Yes	No	No	No

As nouns, percoid fish is a hypernym of sea chub; that is, percoid fish is a word with a broader meaning than sea chub:

sea chub: schooling fishes mostly of Indian and western Pacific oceans; two species in western Atlantic
percoid fish: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of sea chub include percoid, percoidean.

sea chub (noun)	percoid fish (noun)
schooling fishes mostly of Indian and western Pacific oceans; two species in western Atlantic	any of numerous spiny-finned fishes of the order Perciformes