i raised them from when they were little six inchers. i took advice from my lfs and he said as long as i kept them in a group of odd numbers i'd be fine. i grew them out in this same tank and i haven't had any trouble with them. although i have read online that sometimes dominant aros will drive shy ones to the bottom and starve them... i haven't had any issues with my guys though.
as far as being calm, i dont have troubles with aggression but they startle easily and if one gets going and jumping usually the other two get freaked out as well. i've pretty much stationed a lamp next to the tank and i keep that light on 24/7 so they don't get left in the dark and start jumping. and as far as jumping i've only had one incident about 1.5 weeks ago that one of them jumped out at 1 in the morning, luckily i was still awake to stick his ass back in the tank.