In a medium shallow bowl, mix the flour, cornmeal, salt, pepper, garlic powder, chili powder, and cayenne.
In second medium shallow bowl, whisk together the egg and buttermilk.
Heat the oil in a frying pan over medium-high heat. Dip the fish in the buttermilk mixture and then in the flour mixture. Place it in the hot oil. Fry the fish for about 4 minutes on each side until the coating is golden brown. Serve hot.