Rajidae vs fish family

Rajidae and fish family both are nouns.

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

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

Rajidae (noun)	fish family (noun)
bottom-dwelling tropical rays: skates	any of various families of fish