Pufferfish are a distinctive family of tropical and sub-tropical marine fish, also known as blowfish. It is called the puffer fish because when it is threatened, it puffs up to about twice its normal size by gulping water. In this engorged state, the puffer fish can swim at only about half its normal speed.
There are about 100 species of puffer fish. Most puffer fish are found in sub-tropical and tropical marine waters (including coral reefs) in the Atlantic, Pacific, and Indian Oceans. Some puffers live in brackish and fresh water.
Many parts of the blowfish (including the liver, muscles, skin, and ovaries) contain an extremely strong, paralyzing poison called tetrodotoxin. This poison is about a thousand times deadlier than cyanide. There is no known antidote for this poison. Fugu (the prepared flesh of the Japanese puffer fish) is eaten in Japan, but is only cooked by specially-trained chefs who can minimize the amount of poison. Even so, many Japanese diners have died from eating this poisonous delicacy.