In a large pot, combine the fish bones and heads with the water, white wine, onion, celery, carrot, fennel, parsley, garlic, bay leaves, peppercorns and sea salt and bring the fish stock to a simmer over moderately low heat. Simmer the stock for 30 minutes. Strain the fish stock through several layers of moistened cheesecloth. *This fish stock can be made ahead and frozen for up to 1 month. Adapted from Food and Wine.
Find it online: https://www.barrettandtheboys.com/homemade-fish-stock/