sciaenid fish vs percoid

sciaenid fish and percoid both are nouns.

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

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

sciaenid fish: widely distributed family of carnivorous percoid fishes having a large air bladder used to produce sound
percoid: any of numerous spiny-finned fishes of the order Perciformes

Other hypernyms of sciaenid fish include percoid fish, percoidean.

sciaenid fish (noun)	percoid (noun)
widely distributed family of carnivorous percoid fishes having a large air bladder used to produce sound	any of numerous spiny-finned fishes of the order Perciformes