You are in luck!! THAT sort of seafood is plentiful at many WDW restaurants. Almost all have selections like Salmon, Swordfish, Tuna, etc on the menus, prepared in any # of ways.
My favorites are the Flying Fish, and Portobello Yacht Club. Artist Point is great also, especially for " Northwest" type fish selections.
I never, ever would recommend Fulton's to anyone, as the service there borders on pathetic. However, it is a pretty place, and the seafood is good.