Weigh and arrange all ingredients for use.
First, crush the fish carcasses.
Leave them to soak in a bowl with cold water for about 2 hours. Change the water occasionally until it runs clear.
Peel and thinly slice the garlic. Wash the carrots, celery, leeks and onions and cut into small pieces.
Pour the white wine and 1.75l water into a large pan. Bring to the boil and add the prepared vegetables.
Add the fennel, pepper and bay leaf. Allow to simmer for 15 minutes.
Place the carcasses in a sieve, drain and add to the stock.
Boil for about 20 minutes, adding the herbs after 10 minutes.
Carefully skim off the foam from the top.
Finally pour the stock through a sieve lined with a muslin cloth.
Drain well and season with salt.
Serve with fish pieces and vegetable strips as an accompaniment.