Percidae vs fish family

Percidae and fish family both are nouns.

Word	Noun	Adjective	Verb	Adverb
Percidae	Yes	No	No	No
fish family	Yes	No	No	No

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

Percidae (noun)	fish family (noun)
active freshwater fishes; true perches and pike perches	any of various families of fish