Watta Nutty Family

Here is an article that teaches you how to swim with piranhas in the safest manner possible. I think that if you are ever in a position where you need to swim with piranhas, you probably won't have internet access; so it's best if you memorize these tips.

My favorites are #6 and 7:

6.
Avoid making a fuss. Recent studies suggest that desperate piranhas are attracted more by activity than by the scent of blood. Thus, when crossing a river, try to minimize your movement and swim or walk with smooth, fluid motions. Avoid talking, and don't use flashlights or lanterns when crossing at night. However, caimans (South American alligators) are more active and hunt at night. Therefore traversing open water at night, especially at night without lights could be more risky due to the potential for attacks by caimans.

--- So are you better of with a light to ward of the crocodiles, but risking attracting piranhas?

7.
Make a sacrifice. As a last-ditch effort, you can try to create a diversion by releasing an animal carcass or a substantial quantity of raw meat downstream from your desired crossing point. Keep in mind, however, that the piranhas can indeed strip the animal to the bones in a matter of minutes or even seconds, so you'll want to cross very quickly before the fish catch wind of you.

--- It's probably best to travel in groups of people who swim more slowly than you do.