03Meanwhile, heat 2 inches of vegetable oil in a heavy-bottomed pot over medium heat until a deep-fry thermometer registers 375 degrees. Season the fish all over with salt and pepper. Working in batches, dip the fish into the batter, let the excess drip off and lower into the hot oil. Fry until evenly brown, turning with tongs, about 2 minutes per side. Transfer to a paper-towel-lined plate to drain.04Transfer the potatoes to bowls or plates along with the fried fish. Sprinkle with the parsley and serve with malt vinegar, if desired.