Cooking time varies according to the size of the fish and the type of your oven. An oven with a turbo feature at 200 degrees C can cook a sea bass around 700-800 gr in about 25 minutes. You can tell if it is cooked by looking at the color of the fish. If the meat has turned opaque white and the brightness of the fish is gone and reddened, it means it is cooked. You can check with a fork to be sure. Once you have cooked fish in your oven once, you will now know how much time you need to give for which fish in the next cooking.