Cut fish fillet into bite-sized pieces. Remove the head and intestines of the crayfish tails. Place fish and crab tails in a large saucepan, cover with water, bring to a boil and simmer for 10 min.
Remove peel from onions, cut into rings, remove peel from garlic, chop. Leek rinse, clean, cut into fine rings. Carrot rinse, cut into sticks. Rinse fennel, clean, cut off. Sauté vegetables in hot oil. Add thyme, parsley root, bay leaves and peppercorns. Salt, extinguish with wine and add to fish stock form. Leave for 15 minutes, season with salt and pepper.