Has anyone ever had a Piranha just disappear into thin air, and then return again? One of my friends was watching my piranhas, I had one old one, and just got two brand new ones, well they were all getting along just grandly, and all of a sudden there were only two in there, like in a split second. There's no trace of any piranha corpse anywhere, no anything, just now there's two in there, and before there were three. I looked ALL over the tank, and messed with some stuff so as to maybe scare him out of some ridiculous hiding place, but he just can't be found! has this ever happened to anyone??