Brush a large piece of aluminum foil with olive oil. Place the fish fillet on the foil and cover one after the other with the lemon slices, the zucchini slices, the pepper strips and the tomatoes. Pluck the rosemary and thyme sprigs into small pieces and spread over them, then season the whole thing with salt and freshly ground black pepper. Close the foil tightly and cook in the preheated oven at approx. 175 ° for about 15-20 minutes (the cooking time naturally depends on the size of the fish fillet, maybe open the foil briefly after about 10 minutes!).