Wash remains of fish after filleting and put in a suitable pot and add cold water. Add half-chopped garlic with skin, peeled red onion cut in half, parsley sticks and selenium, a tomato sliced in half, olive oil, sea salt, peppercorns. Cook open for about 45 minutes. Strain the broth and add fish remains, sprinkle with chopped fresh parsley.
When making fish soup always put all ingredients in cold water.