Heat deep-fryer to 350ºF. In a large mixing bowl, combine cornmeal, flour, baking powder, baking soda, sugar, and salt. Add buttermilk and egg and whisk to combine. Add oysters to batter, mixing to coat. Take three oysters at a time and roll in hands to form a ball, like a criquette. Dip back in batter and gently drop into fryer. Repeat with remaining oysters, frying until golden brown and crisp. Drain and season with salt. Serve with fermented-chile hot sauce.