To make the Creole Sauce: in a medium, heavy pot, heat the bacon grease over medium heat. Add the flour and stirring constantly with a heavy wooden spoon, cook until a light brown roux forms, about 6 minutes.

Add the onions, celery, and bell pepper and cook over medium heat, until the vegetables are tender, 5 to 6 minutes. Add the garlic, salt, red pepper, and bay leaves, and cook, stirring, for 30 seconds. Add the tomato paste and cook, stirring constantly, until it starts to color, about 2 minutes. Add the tomatoes, oregano, basil, thyme, lemon zest, Worcestershire, and hot sauce, and cook, stirring, for 2 minutes. Add the stock and bring to a boil. Reduce the heat to low and simmer, uncovered, until the sauce thickens and reduces by 25 percent in volume, 20 to 25 minutes, stirring occasionally.

Add the fish to the Creole sauce and cook until firm and cooked through, 5 to 6 minutes. Add the shrimp and parsley, and cook, stirring occasionally, until the shrimp are just cooked through and pink, about 3 minutes. Remove from the heat and discard the bay leaves. Adjust the seasoning, to taste.

Mound the rice in the center of 6 large, shallow bowls. Top with a fish fillet and spoon the Shrimp Creole over the fish. Garnish with green onions and serve immediately.