They actually didn't to bad in the tank, I had 11 in total and they just seemed to stop growing when they reached a size suitable for that environment. I got them when theyw ere just young, under an inch long and they reached that size in about a year, to a year and a half and stayed there for another year, until I had to go out of town for 3 months and leave my tank care to a relative... needless to say I had no fish left when I got back home.
PS. I am now going with a 33 gallon tank.
This is how I hope to end up with a 155 Gallon in the next few years