Predators

A predator that manages to snag a puffer before it inflates won’t feel lucky for long. Almost all pufferfish contain tetrodotoxin, a substance that makes them foul tasting and often lethal to fish. To humans, tetrodotoxin is deadly, up to 1,200 times more poisonous than cyanide. There is enough toxin in one pufferfish to kill 30 adult humans, and there is no known antidote. Some predators, such as tiger sharks and sea snakes, are unbothered by the pufferfish's natural toxins.