Method

1. In a large pot over medium heat, heat oil, then add the fennel and shallots, and cook for 6 minutes until soft and translucent.
2. Add the garlic, oregano, and chili flakes, season with salt and pepper, and cook for 1 more minute until fragrant.
3. Let the mixture boil for 3 to 5 minutes until reduced by half, scraping up the browned bits with a wooden spoon.
4. Add tomatoes, broth, water, bay leaves, and orange zest (if using), stir to combine, then bring to a low simmer, and cook for 20 minutes, while stirring occasionally.
5. Remove the bay leaves and orange zest, then add the clams to the simmering stock, cover, and cook for 5 minutes.
6. Add the mussels in an even layer, then the shrimp, and fish. Do not stir.
7. Cover again and cook for 5 more minutes, or until all clams and mussels are opened and prawns and fish are cooked through and opaque.
8. Discard any unopened mussels and clams and season with salt and pepper to taste.
9. In serving bowls, ladle the soup, top with fennel fronds and chopped parsley, add baguette slices and lemon wedges on the side, and serve.