Preparation

• Locate the bones running vertically down the rockfish and other fish and make a cut on either side of the bones and take them out; use them for the stock, if you like. Cut all the fish fillets into 2- to 3-inch pieces, keeping the different varieties of fish separate. Sprinkle them with salt and toss them gently to distribute the salt; set aside.
• Warm 1/4 cup of the olive oil in a large soup pot; add the leeks, fennel, potatoes, saffron, bay leaves, thyme, 1 Tbs. salt, and a little freshly ground pepper. Stir the mixture well and cook slowly over medium-low heat until the leeks are completely soft but not browned and the potatoes are tender, about 30 minutes. Add the tomatoes, strained tomato juice, and fish stock. Taste and add more salt as needed. Bring to a rapid simmer.
• Add the fish and the remaining 1/4 cup olive oil to the simmering broth, raise the heat to high, and boil for about 10 minutes. Next add the clams and mussels and cook for another 5 minutes. In the last minute, add the squid and parsley. Taste and add salt if needed. Remove the soup from the heat, cover, and let stand for 15 minutes.
• Put a slice of the toasted garlic bread in the bottom of wide-rimmed serving bowls and ladle the soup on top. Serve with a spoonful of the rouille.