The most poisonous fish (to eat) is the puffer fish whose ovaries, eggs, blood, liver, intestines and skin contain a fatally poisonous toxin called tetrodotoxin. Less than 0.1 g (0.004 oz) of this toxin is enough to kill an adult in as little as 20 minutes. Ironically, the poisonous puffer fish is considered a delicacy in Japan. Although the poison is generally removed before they are served, eating puffer fish can still be fatal if the fish was improperly prepared. In some countries, a chef must be certified in order to serve puffer fish because the poisonous parts of the puffer differ slightly from species to species (there are about 120 different species of puffer fish). About 100 diners die each year after eating puffer fish.