Beat the egg with the garlic powder, onion powder, paprika, cayenne pepper, and salt until evenly mixed. Spread the pecan meal into a shallow dish. Dip the walleye fillets into the egg mixture, then press into the pecan flour.
Heat the butter and vegetable oil in a large skillet over medium-high heat. Place the walleye fillets into the pan. Cook until golden brown on both sides and the fish flakes easily with a fork, 3 to 4 minutes per side.