If fish skin sticks to a grill or pan, heat the surface thoroughly and oil it before adding the fish. Do not try to flip the fish too early; leave it undisturbed until the skin releases on its own.
Why does fish skin stick? Proteins in the skin can adhere to the grill grates or pan when they first meet the hot surface. As cooking continues, the fish may release on its own. If you try to flip it before then, the skin can stay behind while the flesh tears away. A grill or pan that is not hot enough can make this worse, because the fish may take longer to release. Wet skin placed directly on a hot surface also increases the chance of sticking.
How can you prevent sticking? Heat the grill or pan over high heat for at least five minutes before adding the fish. When the surface is hot enough, the skin sears quickly and the risk of sticking drops. Brush a thin layer of oil onto the grill grates or pan just before adding the fish to create a barrier between the skin and metal. Pat the skin thoroughly dry with a paper towel and sprinkle it lightly with salt; the salt draws out excess moisture and helps the skin become crisp. After placing the fish on the grill, leave it undisturbed until the edges lift on their own and it can be turned easily with a spatula. This usually takes three or four minutes.
What should you do if the skin still sticks? Instead of forcing the fish to turn, gently slide a thin metal spatula underneath the skin to separate it without breaking up the rest of the fillet. If the skin tears off and stays on the grill, the remaining fish can still be cooked and served; only its appearance is affected, not its taste or safety.
Does the risk vary by fish? Fish with thicker skin, such as salmon or sea bass, is less likely to stick than thin-skinned fish such as sea bream or sole. Thicker skin sears and releases more quickly when it touches the heat. With skinless fillets, the flesh itself can stick, so a very hot, well-oiled grill is just as important. Fish is less likely to stick in a nonstick pan than in a cast-iron or stainless-steel pan, but scratches reduce that advantage. Avoid using a metal spatula in a nonstick pan to help the coating last longer. Lightly dusting the fish with flour before grilling can also help the skin sear faster and more evenly. Letting the fish sit at room temperature for fifteen minutes instead of putting it straight from the refrigerator onto the grill can also help the skin cook and release more evenly.