devilfish vs devil ray

devilfish and devil ray both are nouns.

Word	Noun	Adjective	Verb	Adverb
devilfish	Yes	No	No	No
devil ray	Yes	No	No	No

As nouns, devil ray is a hyponym of devilfish; that is, devil ray is a word with a more specific, narrower meaning than devilfish:

devilfish: extremely large pelagic tropical ray that feeds on plankton and small fishes; usually harmless but its size make it dangerous if harpooned
devil ray: small manta (to 4 feet) that travels in schools

Other hyponyms of devilfish include Atlantic manta, Manta birostris, Mobula hypostoma.

devilfish (noun)	devil ray (noun)
extremely large pelagic tropical ray that feeds on plankton and small fishes; usually harmless but its size make it dangerous if harpooned	small manta (to 4 feet) that travels in schools
bottom-living cephalopod having a soft oval body with eight long tentacles
medium-sized greyish-black whale of the northern Pacific