1. Using vegetable peeler, remove 4 strips of zest from orange, measuring 1×3 inches, careful not to include white pith.
2. Squeeze orange to extract 1/2 cup of juice and set aside.
3. Add olive oil to large soup pot and heat over medium heat. Add onions and fennel. Sautee until onion is translucent and lightly caramelized. About 5-8 minutes.
4. Add carrots, celery, fish stock, bay leaves, orange zest strips, and pepper flakes. Bring to a boil. Immediately reduce heat and simmer until veggies are tender. About 15 minutes.
5. Add tomato paste and canned tomatoes with their juice. Continue to simmer an additional 15 minutes (this additional cooking time is optional but does bring out more sweetness in the tomato).
6. Add garlic and cubed fish. Continue to cook over medium heat for about 5 minutes, or until fish is opaque and flakes easily. Immediately remove from heat to protect not overcooking fish.
7. Discard bay leaf and orange zest. Stir in orange juice.
8. Garnish individual servings with olives slices at the time of serving.

Servings Note:

• It is not recommended to re-freeze fish. Therefore, you wish to make this ahead for freezing, you can make the soup ahead and then add individual servings of fish when reheating. Simply add the fish (or shrimp) to the pot as you reheat the soup to poach it.