To make a roux, heat oil, add flour and cook over medium heat until VERY dark but not scorched, stirring constantly. If using butter, be very careful because it burns easily. Set aside.
In large dutch oven, saute onion, celery, and okra until limp.
Add roux, broth, tomatoes, garlic, bay leaves, crab boil packet, and salt and pepper. (NOTE: If you can't find Crab Boil at your grocery, please refer to Crab Boil Spices by Candie Yoder or # 34801 by Miller)
Simmer for 2 hours.
10 minutes before serving, add all raw fish and seafood and the file powder.