01 - Whisk together buttermilk and hot sauce in a shallow dish. Add catfish fillets, ensuring they're fully coated. Cover and marinate in the refrigerator for at least 15 minutes, up to 1 hour for deeper flavor.
02 - Combine cornmeal, flour, Cajun seasoning, garlic powder, paprika, salt, and black pepper in a large plate or shallow bowl. Mix well to distribute spices evenly.
03 - Pour 1 inch of vegetable oil into a deep skillet or Dutch oven. Heat to 350°F, maintaining temperature throughout frying for optimal crispiness.
04 - Remove catfish from marinade, letting excess drip off. Dredge fillets in the cornmeal mixture, pressing gently to ensure the coating adheres thoroughly.
05 - Fry fillets in batches for 3-4 minutes per side until golden brown and crispy. Transfer to a paper towel-lined plate to drain excess oil.
06 - Combine mayonnaise, dill pickles, capers, lemon juice, Dijon mustard, and parsley in a bowl. Mix well and season with salt and pepper to taste.
07 - Serve fried catfish hot with tartar sauce on the side. Pair with coleslaw, hush puppies, or fries for a complete Southern meal.