Yes, MUDCATS is a Scrabble word!

Letter values in Scrabble US: M 3, U 1, D 2, C 3, A 1, T 1, S 1.

Is it a valid word?

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

flesh of scaleless food fish of the southern United States; often farmed
large catfish of central United States having a flattened head and projecting jaw

Also: flathead catfish, shovelnose catfish, spoonbill catfish, pylodictus olivaris.

Not playable in Scrabble US: GOUJON.