Gasterosteus vs fish genus

Gasterosteus and fish genus both are nouns.

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

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

Gasterosteus (noun)	fish genus (noun)
type genus of the family Gasterosteidae	any of various genus of fish