Pour 2 inches of oil into a large skillet and heat to 325°F.

Cut the fillets lengthwise into manageable pieces. In a shallow bowl, combine the milk, egg, and seasoning salt. Combine the cornmeal, flour, cayenne, black pepper, salt, and garlic powder in a pie plate or cake pan.

Dip each catfish fillet in the egg mixture, then coat with the seasoned cornmeal. Shake the excess meal from the fish, then slowly slide the fillets into the hot oil and fry for about 6 minutes, or until the catfish floats.

Cut into a thick piece to test for doneness. The fish should be flaky white and cooked all the way through.

Drain on paper towels and serve immediately.