Rachycentron vs fish genus

Rachycentron and fish genus both are nouns.

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

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

Rachycentron (noun)	fish genus (noun)
genus and family are coextensive and comprise only the cobia	any of various genus of fish