When preparing baked tilapia, always set the temperature of the oven to 300 degrees Fahrenheit up to 400 degrees Fahrenheit and do not exceed. When it comes to the recommended time, the seafood can be baked for 15 minutes to 20 minutes if covered and 30 minutes to 40 minutes if uncovered.reheat oven to 175 degrees Celsius or 350 degrees Fahrenheit. Remove the seafood from the marinade and arrange in a baking dish. Pour the marinade over the fillets and season with ¼ teaspoon white pepper and ¼ teaspoon cayenne. Place the baking dish in the oven and cook for 30 minutes.