There are over 500 species of piranhas, most of which are herbivores and therefore, do not even eat meat.
Most piranha attacks occur on animals that are injured or dying. The few human attacks recorded usually happened to someone that entered the water with blood on them or that stood in the water while cleaning a fish.
The indigenous people in the rainforest often bathe and swim in the same waters the piranhas inhabit.
In 2010's Piranha 3D, 1,112 boats were used for the spring break massacre set piece.
Originally, Universal Studios wanted to sue the creators of the original Piranha film for spoofing Jaws. However, Steven Spielberg saw the movie in advance and loved it. After that, Universal dropped the lawsuit.