In A Small Bowl, Mix Buttermilk, Water, Salt, And Pepper. Pour Mixture Into A Flat Pan Large Enough To Hold The Fillets. Spread Fish In One Layer Over Bottom Of Pan, Turning To Coat Each Side, And Set Aside To Marinate. In A 2 Gallon Resealable Plastic Bag, Combine The Cornmeal, Flour, And Seafood Seasoning. Add Fish To Mixture, A Few Fillets At A Time, And Tumble Gently To Coat Evenly. Heat Oil In Deep Fryer To 365 Degrees F (185 Degrees C). Deep Fry Fillets Until Golden Brown, About 3 Minutes. Avoid Overcrowding So Fillets Have Room To Brown Properly. Fish Should Be Slightly Crisp Outside, And Moist And Flaky Inside. Drain On Paper Towels.