Atherinopsis vs fish genus

Atherinopsis and fish genus both are nouns.

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

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

Atherinopsis (noun)	fish genus (noun)
a genus of Atherinidae	any of various genus of fish