Wash and clean the tomatoes, cut off 12 slices from about 3 tomatoes. Remove seeds from the remaining tomatoes, cut the flesh into small cubes. Wash sage, shake dry. Pluck off leaves and chop coarsely, except for a little bit for garnishing. Peel, wash and slice the potatoes
Heat 3 tablespoons of oil in a large frying pan, fry the potatoes in it at low heat for about 20 minutes until golden brown, turning from time to time. Season with salt and pepper. Wash the fish, pat dry and season with salt and pepper. Place 3 tomato slices slightly overlapping on each piece of fish. Wrap 2-3 bacon slices around each piece of fish. Heat 2 tablespoons of oil in a coated frying pan. Fry the fish for 2-3 minutes on each side.
Heat butter and 2 tablespoons of oil in another pan. Toss the tomatoes in it. Add sage and fry briefly. Season to taste with salt, pepper and sugar. Arrange fish with potatoes and tomato butter. Garnish with sage