Wash the giltheads and dab them dry. Make a light cross incision from both sides with a very sharp knife. Sprinkle with some lemon juice. Rub the inside and outside with salt and pepper.
Turn in flour and tap lightly. Fry in hot oil for 8-10 minutes on each side. In the meantime, peel and wash the potatoes. Cook in boiling salted water for about 20 minutes. For the sauce, drain the pumpkin and collect the juice.
Cut the cubes a little smaller. Peel garlic and onion, dice finely. Puree the canned tomatoes. Carve chilli pepper lengthwise, remove seeds. Wash the pod and cut into fine rings. Heat the fat.
Fry the garlic and onion in it. Deglaze with canned tomatoes and 100 ml pumpkin juice. Bring to the boil. Stir in seasoning mixture. Season with salt and some lemon juice. Warm the pumpkin cubes in it.
Put the sauce on a plate. Arrange fish and potatoes on top. Serve garnished with parsley, lemon and lime slices.