fish genus vs genus

fish genus and genus both are nouns.

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

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

fish genus (noun)	genus (noun)
any of various genus of fish	a general kind of something
	(biology) taxonomic group containing one or more species