Yes, KINGFISHES is a Scrabble word!

Letter values in Scrabble US: K 5, I 1, N 1, G 2, F 4, I 1, S 1, H 4, E 1, S 1.

Is it a valid word?

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

the lean flesh of any of several fish caught off the Atlantic coast of the United States
large edible mackerel of temperate United States coastal Atlantic waters
small silvery marine food fish found off California
any of several food and game fishes of the drum family indigenous to warm Atlantic waters of the North American coast
large game fish of Australia and New Zealand

Also: scomberomorus regalis, white croaker, genyonemus lineatus, seriola grandis.

Not playable in Scrabble US: CHENFISH.