Place the fish in a pot with a whole clove of garlic, a quarter of the tomatoes, a teaspoon of chopped parsley, a third of the wine and 6 cups of water. Boil and simmer for 30 minutes. Strain and save the resulting broth.
Clean the mussels and clams. Cut the fish into 2.5 inch pieces. Chop the rest of the garlic and cut the rest of the tomatoes into large pieces.
Heat the oil in a pot. Cook the onion until soft, about 20 minutes. Add the garlic and two thirds of parsley. Cook for 10 minutes.
Add the tomatoes and chili peppers. Cook for 10 more minutes, stirring regularly until the tomatoes have dissolved. Pour in the rest of the wine, raise the heat to boil and let it bubble for 2 minutes. Add the broth, plenty of salt and pepper ,and saffron. Let it boil. Reduce and simmer uncovered for 15 minutes.
Add the fish, oysters, squid, and prawns. Cook for no more than 20 minutes.
Garnish with parsley before serving.