Fish fillet salt it and left. In the pan put the sliced ​​potatoes into thin slices to cover the bottom of the tray. On them put coarsely chopped onion (may he be cut circles) and on onion put fish fillet. Then add the tomato paste mixed with pepper and olive oil. Cover with foil and bake in a moderate oven of 180C degrees for about 30 minutes. Check whether the potatoes are ready when they are ready removing fthe oil, bake slightly on top and then sprinkle with parsley.