Heat 1 to 2 tablespoons oil in large skillet over medium-high heat; add okra and sauté 1 to 2 minutes to prevent stringiness. Remove okra with a slotted spoon and set aside.
Add remaining oil to skillet and heat until it is just at the smoking point; gradually add flour, whisking constantly to avoid burning, and cook until mixture turns dark brown to make a roux. The darker the roux, the richer the taste, but do not let it burn. Add onion, bell pepper and celery, a little at a time, and continue stirring while mixture cooks. Stir in garlic. Remove from heat.
Bring stock to a boil in a large kettle. Stir roux into seafood stock, a little at a time, stirring constantly. Add okra, bay leaves, salt, peppers, thyme and oregano. Simmer until okra is tender, 10 to 15 minutes. Add shrimp and fish. Cook 2 minutes or until shrimp is pink and fish is firm.Makes about 1 gallon Source: