Prepare the Catfish: Pat the catfish fillets dry with paper towels. Removing excess moisture helps the coating stick better and creates a crispier crust.
Make the Seasoned Coating: In a shallow dish, combine cornmeal, flour, Cajun seasoning, paprika, garlic powder, onion powder, black pepper, salt, and cayenne pepper. Mix until evenly combined.
Soak the Catfish: Pour the buttermilk into a separate shallow bowl. Dip each catfish fillet into the buttermilk, making sure both sides are coated. Allow excess buttermilk to drip off.
Coat the Fillets: Place each buttermilk-coated fillet into the seasoned cornmeal mixture. Gently press the coating onto both sides until completely covered.
Heat the Oil: Heat the vegetable or peanut oil in a large skillet or Dutch oven to approximately 350°F. Use a kitchen thermometer for the most accurate temperature.
Fry the Catfish: Carefully place the coated fillets into the hot oil without overcrowding the pan. Fry until golden brown and crispy, turning once during cooking. The fish should reach an internal temperature of 145°F.
Drain the Catfish: Transfer the fried catfish to a wire rack set over a baking sheet or a paper towel-lined plate. Allow excess oil to drain.
Serve: Serve the crispy catfish immediately with fresh lemon wedges, tartar sauce, coleslaw, hush puppies, fries, or your favorite Southern side dishes.