genus Polyodon vs fish genus

genus Polyodon and fish genus both are nouns.

Word	Noun	Adjective	Verb	Adverb
genus Polyodon	Yes	No	No	No
fish genus	Yes	No	No	No

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

genus Polyodon (noun)	fish genus (noun)
type genus of the Polyodontidae	any of various genus of fish