There are various types of ready-to-eat or instant jellyfish products, which can be found in most Asian supermarkets. There are some which contain only heads and some which contain tentacles; any type will work for this recipe, as long as it isn’t the salted dried type. Ready-to-eat jellyfish is typically sold in 5.2-ounce packages with seasoning packets. If you purchase packages of another size, make sure you have at least 10 ounces of jellyfish once you remove the seasoning packets.