Yes, DEVILFISH is a Scrabble word!

Letter values in Scrabble US: D 2, E 1, V 4, I 1, L 1, F 4, I 1, S 1, H 4.

Is it a valid word?

DEVILFISH is a valid word in the official Scrabble dictionary (US), the UK Scrabble Dictionary and Words with Friends (ENABLE).

medium-sized greyish-black whale of the northern Pacific
bottom-living cephalopod having a soft oval body with eight long tentacles
extremely large pelagic tropical ray that feeds on plankton and small fishes; usually harmless but its size make it dangerous if harpooned

Also: grey whale, gray whale, eschrichtius gibbosus, eschrichtius robustus, manta ray.