Yes, HAGFISHES is a Scrabble word!

Letter values in Scrabble US: H 4, A 1, G 2, F 4, I 1, S 1, H 4, E 1, S 1.

Is it a valid word?

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

eellike cyclostome having a tongue with horny teeth in a round mouth surrounded by eight tentacles; feeds on dead or trapped fishes by boring into their bodies

Also: slime eels.