1. Preheat oven to 350 degrees Fahrenheit.
2. Place cod in an oven-safe baking dish. Drizzle with two tablespoons olive oil and sprinkle with half a teaspoon salt, a quarter teaspoon pepper and oregano. Place tomatoes, raisins, pine nuts, and olives on top of and around cod. Lay slices of potatoes on top. Drizzle with remaining two tablespoons olive oil, half teaspoon salt, and quarter teaspoon pepper.
3. Cover tightly and cook for 25 minutes. Uncover and cook an additional 10 minutes or until fish is cooked through and potatoes are slightly browned. Serve warm with toppings and sauce from the pan.