Make the batter by whisking the buttermilk, egg, mustard, and hot sauce together.
Marinate the filets in the batter for at least 30 mins.
Make the crispy coating: in a shallow dish mix together the cornmeal, paprika, cayenne pepper, dill, garlic powder, salt, and pepper.
Remove each filet from the marinade, shaking off the excess, place it in the dish with the breading, and coat it on both sides.
Heat the oil in a large skillet over medium-high heat. Once hot, fry the filets until golden brown on both sides, about 3 minutes on each side.