Heat the vegetable oil in a large saucepan until hot.
Whisk flour, baking powder, and sparkling water in a bowl to create a thick batter.
Stir in ice cubes and dip the sea bass fillet into the batter.
Fry the fish for 4 minutes until golden-brown and drain on paper.
Boil halved new potatoes and unpeeled garlic in salted water for 12 minutes.
Drain the potatoes and peel and roughly chop the boiled garlic cloves.
Crush potatoes with a fork and mix in garlic, lemon juice, parsley, and seasoning.
Serve the fish on top of the potatoes with lemon wedges.