Belonidae vs fish family

Belonidae and fish family both are nouns.

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

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

Belonidae: ferocious fishes of warm regions resembling but unrelated to the freshwater gars
fish family: any of various families of fish

Belonidae (noun)	fish family (noun)
ferocious fishes of warm regions resembling but unrelated to the freshwater gars	any of various families of fish