Wash the potatoes and cook for about 20 minutes. Then rinse with cold water, peel and leave to rest for a while. In the meantime wash, clean and slice the tomatoes. Wash the fish and pat dry.
Peel the garlic and press it through a garlic press. Mix with lemon juice. Cut the potatoes into slices as well. Put 2 sheets of parchment on a baking tray. Layer potato and tomato slices in flakes.
Season with salt and pepper. Cover with 1 piece of fish. Drizzle lemon juice on top. Sprinkle with salt, pepper, dried fennel seeds and herbs. Seal parchment to one parcel each.
Cook in the preheated oven (electric cooker: 200 °C/ circulating air: 175 °C/ gas: level 3) for about 20 minutes.