Well-known saltwater species of the pufferfish of the Tetraodontiformes are the Porcupinefish, Boxfish, Filefish and the Triggerfish. Three common edible species of pufferfish, Takifugu obscurus, T. flavidus and T. rubripes are cultured in various locations in the Yangtze River, the East Sea, the Yellow Sea, the South Sea and the Bohai Sea of China. Some pufferfish species can be kept as aquarium fish in freshwater, brackish and saltwater aquariums. The toxin of pufferfish is variously used as a defensive biotoxin to ward off predation. Majority of the pufferfish species are toxic with a potent neurotoxin viz tetrodotoxin, a potent neurotoxin and the paralytic saxitoxin is seen in certain species as the secondary toxin. Pufferfish poisoning has occurred in several countries including Japan, Korea, Thailand and The Philippines. Some species of pufferfish are considered vulnerable due to pollution, habitat loss, and overfishing, but most populations are considered stable.