The head of this fish was found in Fiji. A large fish seems to have attempted to eat a puffer fish, which inflated, and killed the large fish with its toxin, tetrododoxin. Under the water the fish-urchin while trying to attack her when she has nowhere to hide, swollen, swallowing water. In this form it is almost invulnerable. Large predatory fish sometimes try to swallow it all the same, but it ends tragically for them: they are found dead with stuck in their throat victim, as in this case.
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.
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