01 - Combine buttermilk and hot sauce in a shallow dish. Add fish fillets, ensuring they are fully submerged, and marinate for at least 15 minutes to tenderize and infuse flavor.
02 - In a large mixing bowl, whisk together cornmeal, flour, Cajun seasoning, salt, black pepper, paprika, and cayenne pepper until thoroughly blended.
03 - Pour about 1 inch of vegetable oil into a large skillet or deep fryer. Heat to 350°F, maintaining temperature throughout the frying process for optimal crispiness.
04 - Remove fillets from marinade, allowing excess liquid to drip off. Press each fillet firmly into the breading mixture, turning to coat all sides evenly and ensuring a thick, even layer.
05 - Place coated fillets in hot oil without overcrowding. Fry for 3-4 minutes per side until golden brown and fish flakes easily with a fork. Transfer to paper towel-lined plate to drain excess oil.
06 - Combine mayonnaise, chopped pickles, capers, lemon juice, Dijon mustard, and parsley in a small bowl. Season with salt and pepper to taste, mixing until smooth and well incorporated. Refrigerate until serving.
07 - Plate hot fish fillets immediately with chilled tartar sauce. Accompany with lemon wedges, coleslaw, or fries for a complete Southern meal.