Heat olive oil over medium heat in a heavy-bottomed soup pan.
Add onion, fennel bulb, leek, garlic and a pinch of salt, and slowly sweat ingredients until tender but not browned, about 10 minutes.
Soak saffron in wine, and heat in microwave for 1 minute.
Add wine and saffron mixture, and cook for 2 minutes, scraping any brown bits from bottom of pan.
Add tomatoes, orange juice, saffron and stock, and bring to a boil. Reduce heat to medium, and simmer until liquid is reduced by half, about 20 minutes.
Add catfish, and cook 2 minutes. Add shrimp, clams and mussels; cook for an additional 2 minutes. Season to taste with salt and pepper.
Ladle into large bowls. Garnish with parsley, and serve with toasted French bread slices.