Wash and dry the fish with a paper towel. Cut the onion into half rings and put on the form covered with foil with a margin so that you could then wrap the fish.
Put bay leaf and pepper in peas, cut half a lemon into circles and put onion.
Salt the fish to taste and put in a mold, pour the juice of the remaining lemon.
Cover the fish tightly with foil and place in a preheated oven to 200 degrees for 20 minutes.
Red fish baked in foil is ready, serve in any side dish.