jewfish vs sciaenid fish

jewfish and sciaenid fish both are nouns.

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

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

jewfish: large important food fish of Australia; almost indistinguishable from the maigre
sciaenid fish: widely distributed family of carnivorous percoid fishes having a large air bladder used to produce sound

Other hypernyms of jewfish include sciaenid.

jewfish (noun)	sciaenid fish (noun)
large dark grouper with a thick head and rough scales	widely distributed family of carnivorous percoid fishes having a large air bladder used to produce sound
large important food fish of Australia; almost indistinguishable from the maigre