Toss the shrimp in 1/4 t each Old Bay and creole seasoning. Set aside. Separately, do the same with the cod.
In a large, heavy pot, heat the olive oil. Add the sausage and cook over high heat, stirring occasionally, until well browned. Add the veggies and season with a pinch each salt (to get them to soften) and pepper. Cook, stirring regularly, until softened (~5 minutes).
Add 1 t Old Bay, 1/2 t creole seasoning, and rice. Add the chicken stock and thyme; season well (at least 1/2 t salt), and bring to a boil. Use a wooden spoon to quickly scrape up the browned bits from the bottom of the pot. Cover and cook over med-low heat for 10 minutes.
Stir in the shrimp. Layer the fish on the rice, recover, and cook ~10 minutes until rice is cooked. Yield: 4-6 servings.