Ephippidae vs fish family

Ephippidae and fish family both are nouns.

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

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

Ephippidae (noun)	fish family (noun)
small family comprising the spadefishes	any of various families of fish