Piranhas have developed a fearsome reputation ... They are responsible for numerous fatal shark attacks, making them one of the most dangerous fish species in the world. While not technically ...

They also have long venomous spines that carry deadly poison, making them one of the most dangerous fish in the ocean ... attacking boats in recent years. Piranhas also have a bad reputation ...

Piranhas are fish that live in the Amazon River and lakes ... isn't formed because the piranhas realise they'll be more dangerous when hunting together - it's actually a defensive tactic.