Opisthognathidae vs fish family

Opisthognathidae and fish family both are nouns.

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

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

Opisthognathidae (noun)	fish family (noun)
jawfishes	any of various families of fish