1. Clean and wash the Fish. 2. Boil the remaining bones and heads in water with spices about 2 minutes and then drain through sieve. 3. Melt margarine and fry finely chopped onions and Mushrooms until golden brown about 10 minutes. 4. Add flour, tomato paste, fish bouillon and fish (cut into small pieces). Boil about 10 minutes. 5. Add finely chopped pickle, capers, dill and lemon (seeds removed). Serving: Finally add sour cream to each serving and serve hot.