Cut fish into 80 mm wide stripes. Preheat oven to 180°C. Halve bell peppers, remove seeds and cut into stripes. Chop onion finely und sautee in butter. Add sourcrout, bell pepper stripes and pressed garlic. Fold in cream and sour cream and season to taste with salt, pepper and paprika powder. Let all simmer about 15 minutes.
Put sourcrout into a casserole. Season fish filets with salt and pepper and put them upon sourcrout and cook in oven about 10-15 minutes.
Serve and sprinkle with dill.