Grilling is suitable both for small, whole fish, such as mullet, or for fillets of fish, and even for some shellfish such as prawns or lobsters. It also takes two forms: over heat on a charcoal grill or barbecue; or under a grill giving top heat only. If the fish is thin or only a fillet, the flesh or cut side should be done first to seal in its juices; alternatively, a tray can be used instead of a rack, in which case the fish will not need turning. Always preheat the grill on its highest setting so that the fish seals quickly, trapping its juices; if it is a large piece, then turn the heat down a little so that the fish cooks gently and without burning. When grilling whole fish, it is best to score the flesh a few times so that the heat can penetrate more effectively, and remember that it will need basting occasionally. If it is not scored, the outside of the fish will dry and burn before the inside is cooked.