Gerridae vs fish family

Gerridae and fish family both are nouns.

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

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

Gerridae (noun)	fish family (noun)
an arthropod family that includes water striders	any of various families of fish
mojarras