Fry half the fish. When the oil is ready, add half of the floured fish to the batter and stir to coat. Pick up the fish one piece at a time, let the excess batter drip back into the bowl, and carefully place in the oil. Don’t stack pieces on top of each other or they will stick together. Fry, stirring and flipping them occasionally with tongs, until cooked through and golden brown, about 5 minutes.