barrelfish vs butterfish

barrelfish and butterfish both are nouns.

Word	Noun	Adjective	Verb	Adverb
barrelfish	Yes	No	No	No
butterfish	Yes	No	No	No

As nouns, butterfish is a hypernym of barrelfish; that is, butterfish is a word with a broader meaning than barrelfish:

barrelfish: blackish fish of New England waters
butterfish: small marine fish with a short compressed body and feeble spines

Other hypernyms of barrelfish include stromateid, stromateid fish.

barrelfish (noun)	butterfish (noun)
blackish fish of New England waters	small marine fish with a short compressed body and feeble spines
	slippery scaleless food fish of the northern Atlantic coastal waters
	any of numerous small flat Atlantic food fish having smooth skin