Peel potatoes, dice coarsely and cook in boiling salted water for about 20 minutes. Meanwhile, bring wine, bay leaf and honey to the boil in a saucepan and simmer for 2-3 minutes. Drain the sauerkraut and add to the hot stock.
Braise for 10 minutes at low heat. Meanwhile, wash and pat dry the pike-perch. Cut diagonally into 4 slices. Sprinkle with lemon juice and season with salt. Drain and steam the potatoes.
Add warm milk and butter. Mash with a potato masher and keep warm. Heat oil in a frying pan. Fry the zander on the skin side for 4-5 minutes. Arrange sauerkraut, mashed potatoes and fish together on plates.
Possibly garnish with lemon slices.