hi, i'm a noob with piranhas but i started with 8pcs 1/2 inch Juvi. RPB as well...
they are housed in a 48"x30"x30" tank...
yes, they will hide when newly introduced to the tank..
now, they have reached a size of 1" and i can always see them...
so don;t worry about it...
they have lots driftwood as cover...
my tank pic is posted in page 5 at the sticky..
one thing i noticed is that some of them tend to have nipped fins but some not... no big deal because not much damage done...
hope this answer helps...
NEED HELP TOO...
*** is this normal?? where some have nipped fins and some has not..
is this due to the fact that i provide lots of driftwood which some claimed as their territory?