Wash the potatoes thoroughly and boil them in salted water for 20 minutes. Drain, peel and slice the potatoes. In the meantime, bake the pollack fillets in the preheated oven (electric cooker: 225 ° C/ gas: level 4) for 15-20 minutes until golden brown.
Peel and finely chop the onion. Peel egg and cut into small cubes. Chop cucumbers finely. Mix remoulade, yoghurt and cucumber water. Season with salt and pepper. Add onions, diced eggs, cucumber and capers and fold into the potatoes.
Serve with the fish.