With this halibut recipe, you don't have to worry about the fish sticking to the grill, because it's cooked on a cedar plank. If you put the fish straight on the grill grates without the plank, you want to make sure your grates are clean and oiled. You'll also want to add oil to the fish. Then, let it cook until it releases easily with a spatula. If you try to remove it too early, it will stick.