scombroid vs percoid fish

scombroid and percoid fish both are nouns.

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

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

scombroid: 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 include percoid, percoidean.

scombroid (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