lol, I kept 8 Red Belly Piranha's for over 3 years, loved them, but eneded up selling them as I needed the tank.
These fish believe it or not are very shy, everytime I went near, or put my hands in the tank to clean, they would hide behind the grasses and plants.
Saying that, they did like their earthworms, poor weeee worms didn't stand a chance.