Boil potatoes in their skins. Peel and slice them.
Cut smoked bacon into little sticks. Make an incision in each fish chunk, and insert the bacon pieces into them.
Butter a baking-serving casserole thickly. Place potato slices on the bottom of the casserole, add a layer of the fish, and sprinkle with salt and paprika. Cover with onion slices, green pepper slices and finally with tomato slices.
Melt remaining butter and pour on top of the casserole. Bake in a 375°F. oven for 30 minutes.
Mix flour with sour cream, and spread it over the top of the half-finished casserole. Put back into oven for 20 to 30 minutes more.