scombroid fish vs percoid fish

scombroid fish and percoid fish both are nouns.

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

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

scombroid fish: important marine food and game fishes found in all tropical and temperate seas; some are at least partially endothermic and can thrive in colder waters
percoid fish: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of scombroid fish include percoid, percoidean.

scombroid fish (noun)	percoid fish (noun)
important marine food and game fishes found in all tropical and temperate seas; some are at least partially endothermic and can thrive in colder waters	any of numerous spiny-finned fishes of the order Perciformes