I have to agree with the other posters. Since I was little, I only remember hearing horrifying things about piranhas (they could eat a whole cow in seconds, fishermen would lose limbs fishing in the Amazon, and even small children had been killed). Funny thing is, those enormous teeth I always heard about are not that enormous. Another thing, there must be blood in the water to force the feeding frenzy. Still, I would not want to get into water with one.