Asian seabass vs fish species

Asian seabass and fish species both are nouns.

Word	Noun	Adjective	Verb	Adverb
Asian seabass	Yes	No	No	No
fish species	Yes	No	No	No

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

Asian seabass: a species of large perch noted for its sporting and eating qualities; lives in marine, estuary, and freshwater habitats
fish species: a species of fish

Asian seabass (noun)	fish species (noun)
a species of large perch noted for its sporting and eating qualities; lives in marine, estuary, and freshwater habitats	a species of fish