To make the stock Put all the fish bones, heads, skins, and scraps into a stockpot and cover with cold water. Bring it to a boil, then dump the water, saving all the fish parts.
Refill the pot with just enough water to cover the fish parts. Add all the other stock ingredients, and bring to the lightest possible simmer, with bubbles breaking only occasionally. Hold the stock at that temperature, uncovered, for about 45 minutes. Skim off the scum as the pot simmers.
Strain the stock and discard all the solids. Return the liquid to a slow simmer while you work on the rest of the recipe. Turn the oven on to 325 degrees.
In a large skillet or roasting pan, heat the olive oil over medium-high heat until fragrant. Add the onions, fennel, garlic, and crushed red pepper. Cook until the onions are clear, but don't let them brown. Add the fresh and canned tomatoes, tomato juice and wine, and bring to a boil. Hold at a moderate boil for about two minutes.
Lower the heat to medium. Add a cup of the fish stock, the fish fillets and the squid. Return to a simmer and let it all cook for for three minutes.
Add enough more fish stock that it comes up about halfway the sides of the fish in the pan. Return to a light boil.
Add the saffron and the shrimp to the pan and cook for about a minute. Add the crabmeat, oysters, salt, and green onions and cook for another minute, agitating the pot to distribute the ingredients. Add salt and cayenne pepper to taste.
Cover the pan with aluminum foil and put it into the 325-degree oven. Cook for between four and eight minutes, depending on the size of the fish pieces. The fish is cooked when it's opaque everywhere. If you're using whole fish, insert the tines of your kitchen fork into the thickest part of the fish for about five seconds. Carefully touch the tines to your lips. If it feels even a little warm, the fish is done.
Taste the broth and adjust salt, pepper, and Tabasco. Divide the seafood equally among four to six bowls, and ladle the broth and vegetables over everything. Garnish with fresh chopped parsley. Serve with toasted French bread round slices spread with spicy garlic mayonnaise.