Im pretty sure its a rhom as well. Nice fish give it a couple weeks or months before it gets used to you. Most my p's freak with sudden movement. My rbs I wouldn't really see when I first had them, now they come to the top everytime they see me. one of my elongs would sit in the same spot most of the time, my other one after a few days was eating out of my hand. It all depends on the fish, give it time and it will warm up to you.
and how does color vary??? the guy at fish store said he will be lighter and dark but still have that shine to him i see the shine and glitter looking shine in his body up close... guy said it was a Gold diamond Piranha but who knows i guess....