Platichthys vs fish genus

Platichthys and fish genus both are nouns.

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

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

Platichthys: a genus of Pleuronectidae containing the starry flounders (Platichthys)
fish genus: any of various genus of fish

Platichthys (noun)	fish genus (noun)
a genus of Pleuronectidae containing the starry flounders (Platichthys)	any of various genus of fish