In a medium bowl, whisk together the buttermilk, mustard, Essence, hot sauce, and garlic. 

Cut the fish into 5- or 6-inch long pieces about 1 inch wide. Add the fish strips to the bowl with the buttermilk-mustard mixture and turn so that the pieces are evenly coated. Set aside to marinate while you assemble the remaining ingredients. 

Add enough oil to a large Dutch oven to fill it halfway. Preheat the oil to 365 degrees F over medium-high heat. 

In a shallow bowl or in a resealable food-storage plastic bag, combine the flour, cornmeal, corn flour, and salt. Stir or shake to combine. 

Working in batches, remove a handful of fish fingers from the marinade and dredge in the flour mixture until completely coated. Tap to remove any excess. One at a time, gently slip the fish into the hot oil. Fry until the fish is crispy and golden brown and floats on the surface of the oil, usually 3 to 4 minutes. 

Using a slotted spoon or a spider, transfer the fried fish to paper towels or a wire rack to drain, then sprinkle lightly with Creole Seasoning and serve with tartar sauce, hushpuppies, and lemon wedges. Serve hot.