Pufferfish are generally believed to be the second most poisonous vertebrates in the world, after the golden poison frog. Certain internal organs, such as liver, and sometimes the skin, are highly toxic to most animals when eaten; nevertheless, the meat of some species is considered a delicacy in Japan (known as fugu), when prepared by chefs who know which part is safe to eat and in what quantity. Pufferfish are poor swimmers, but can quickly ingest huge amounts of water to turn themselves into a virtually inedible ball several times their normal size.
