Peel and wash the potatoes and cook them in boiling salted water for about 20 minutes. In the meantime clean, wash and dice the peppers. Clean, wash and slice the zucchini. Peel and chop the onion.
Heat the oil in a casserole dish. Fry the zucchini, bell pepper and onion in it while turning. Dust with 1 1/2 tbsp. flour, sauté. Deglaze with stock and whipped cream. Bring to the boil and simmer at low heat for about 2 minutes.
Wash the dill, shake dry and chop finely, put 1 teaspoon aside for garnishing. Mix the rest of the dill with the vegetables. Season with lemon juice, salt, pepper and sugar.
Wash the fish, dab dry, cut into 8 slices, season with salt and pepper. Turn in 2 1/2 tablespoons of flour. Heat clarified butter in a frying pan and fry the fish for 4-5 minutes. Meanwhile wash parsley, shake dry and chop finely.
Drain the potatoes, let them steam briefly, sprinkle with parsley. Sprinkle zucchini vegetables with remaining dill. Arrange vegetables, fish and parsley potatoes garnished with lemon slices.