For years I wanted Piranhas but the wife always talked me out of it. But after a long time of pouting
. I finally got RBP's a while back.
I purchased them at around 1 1/2 " in size and fell in love immediately. Well after a while they all grew to around 5", and I kept up with my normal routine as they did when they were little. Putting my hand in the tank to adjust loose plants, clean, etc. They would always stay on one side of the tank while i did my thing.
Well the little buggers have grown up and one day I was moving a piece of driftwood over to one side of my tank when my largest decided to think it was din-din time and glanced my right pinky, turning the water red.
At first I thought, that little **** he must of just caught me, till I looked down and seen the flap hanging from my finger
That part did not bother me, I work in construction and get cuts all the time, the part that bothered me was my wife saying "SEE I told you" 
Lesson learned, no matter how much you trust your Piranha, they will eventually eat your fingers lol.
Now I use real long tongs and a divider to maintenance my tank.

I purchased them at around 1 1/2 " in size and fell in love immediately. Well after a while they all grew to around 5", and I kept up with my normal routine as they did when they were little. Putting my hand in the tank to adjust loose plants, clean, etc. They would always stay on one side of the tank while i did my thing.
Well the little buggers have grown up and one day I was moving a piece of driftwood over to one side of my tank when my largest decided to think it was din-din time and glanced my right pinky, turning the water red.
At first I thought, that little **** he must of just caught me, till I looked down and seen the flap hanging from my finger


Lesson learned, no matter how much you trust your Piranha, they will eventually eat your fingers lol.
Now I use real long tongs and a divider to maintenance my tank.