Cut the fish into uniform chunks 1-2 inches long. Cut shrimp in half lengthwise. Place fish and shrimp in a shallow non-reactive dish and sprinkle with salt and pepper. Cover and refrigerate while making the broth.
In a large, heavy saucepan over medium heat, warm the olive oil. Add the onions, zucchini and bell peppers and cook, stirring, until tender, about 10 minutes.
Add the garlic, red pepper flakes, oregano and bay leaf and cook for 2 minutes. Add the tomatoes and simmer for 3 minutes longer. Add the wine and stock and simmer, uncovered for another 10 minutes.
Season to taste with salt and pepper. Add the fish and shrimp and simmer, uncovered, until the fish is opaque and the shrimp is pink. Add the basil. Serve at once with hearty French bread and a good red wine.