Wrap the bay leaf, rosemary, and fennel seeds in a cheesecloth bag. Set the sachet aside. Heat the oil in a very large pot over medium heat. Add the chopped fennel and shallots and saute until the fennel is tender, about 6 minutes. Season with salt and pepper. Add the tomatoes with their juices, the wine and fish broth. Stir in the tomato paste. Add the sachet. Bring to a boil. Reduce the heat to medium-low. Cover and simmer until the flavors blend, about 10 minutes.
Add the clams to the cooking liquid. Cover and cook until the clams open, about 6-8 minutes (discard any clams that do not open). Using tongs, transfer the clams to a bowl. Repeat with the mussels. Add the potatoes to the cooking liquid and simmer until they are almost tender, about 10 minutes. Add the fish, shrimp, and corn. Simmer until the fish and shrimp are just cooked through, and the corn is heated through, about 5 minutes. Return the clams and mussels to the soup. Stir in the parsley. Season the soup to taste with salt and pepper.
Ladle the soup into bowls and serve with the Garlic Toasts with Red Pepper Aioli.
To make the garlic bread: Preheat the oven to 400 degrees F.
Drizzle the oil over the bread slices. Arrange the bread on a baking sheet. Sprinkle with salt and pepper. Bake until the bread is crisp and golden, about 5 minutes. Immediately rub the garlic cloves over the hot toasts.
To make the aioli: Finely chop the garlic in the food processor. Add the peppers and blend until almost smooth. Blend in the mayonnaise. With the machine running, blend in the oil. Season the aioli, to taste, with salt and pepper. Transfer the aioli to a small bowl. (The aioli can be made 2 days ahead. Cover and refrigerate.)
Spread the aioli over the toasts and serve.