oyster fish vs Opsanus tau

oyster fish and Opsanus tau both are nouns.

Word	Noun	Adjective	Verb	Adverb
oyster fish	Yes	No	No	No
Opsanus tau	Yes	No	No	No

As nouns, Opsanus tau is a hypernym of oyster fish; that is, Opsanus tau is a word with a broader meaning than oyster fish:

oyster fish: a variety of toadfish
Opsanus tau: bottom-dwelling fish having scaleless slimy skin and a broad thick head with a wide mouth

Other hypernyms of oyster fish include toadfish.

oyster fish (noun)	Opsanus tau (noun)
a variety of toadfish	bottom-dwelling fish having scaleless slimy skin and a broad thick head with a wide mouth