Ingredients:

• 1 pound raw medium shrimp, peeled and deveined, shells reserved
• 3 cups water
• 1 1/2 pounds skinless catfish or cod fillets (halve fillets lengthwise if large), cut crosswise into 1-inch strips
• 1 teaspoon kosher salt, plus more to taste
• 2 tablespoons olive oil, plus more for drizzling
• 2 tablespoons all-purpose flour
• 1 large white onion, chopped
• 1 large red bell pepper, chopped
• 2 medium celery stalks, chopped
• 3 medium garlic cloves, chopped
• 1 (15-ounce) can diced tomatoes, undrained
• 8 ounces fresh okra, stemmed, cut crosswise into  1/2-inch pieces, or 2 cups frozen sliced okra
• 2 tablespoons Worcestershire sauce
• 2 teaspoons chopped fresh thyme
• 2 fresh or dried bay leaves
• 2 teaspoons Creole seasoning
• 1/2 teaspoon black pepper, plus more to taste
• Cooked black rice for serving
• Thinly sliced scallions, for garnish

Instructions:

1. Combine shrimp shells and 3 cups water in a medium saucepan. Bring to a simmer over medium. Remove from heat, and let stand 15 minutes. Pour mixture through a fine wire-mesh strainer into a bowl; discard solids. Set stock aside. Toss together catfish pieces and salt in a large bowl. Cover and chill until ready to use, up to 1 hour.
2. Heat oil in a large Dutch oven over medium. Add flour; cook, whisking constantly, until smooth and lightly browned, about 1 minute. Add onion, bell pepper, celery, and garlic. Cook, stirring often and scraping bottom of Dutch oven to prevent scorching, until softened, 8 to 10 minutes. Stir in shrimp stock, tomatoes with juices, okra, Worcestershire, thyme, bay leaves, Creole seasoning, and black pepper. Bring to a simmer over medium-high. Reduce heat to medium-low; cover and simmer until okra is almost tender, about 15 minutes.
3. Stir in catfish and shrimp, and reduce heat to low. Cover and cook until catfish and shrimp are cooked through, 5 to 8 minutes. Remove and discard bay leaves. Season to taste with salt and pepper. Serve with black rice; garnish servings with scallions, and drizzle with olive oil.