Place cornmeal, flour, cayenne, paprika, salt, and pepper in a shallow dish and whisk to thoroughly combine.
Heat vegetable oil over medium heat in a 12-inch cast iron skillet to 350°F. Line a plate with several layers of paper towels; set aside.
Use a paper towel to blot the fish pieces dry, season on all sides with salt and pepper, then dredge in the cornmeal mixture, being sure to cover all sides. Tap fish pieces lightly to shake off any excess coating.
Fry fish in batches, turning once, until deep golden brown and crisp on the outside with a flaky interior, about 6 minutes total.
Remove fish from the pan with a slotted spatula to the paper-towel-lined plate to drain. While the pieces are still hot, season well with salt. Serve with lemon wedges and rémoulade.
For the rémoulade: Mix all ingredients together and serve chilled.
-The original recipe for frying the catfish calls for 6 cups veggie oil, I reduced it to about 1, and fried in batches of about 4 fillets at a time.