now, i have my Black Ghost knife in my 55g, going to be moved to a bigger tank soon... but he fits in there fine and i've had him for almost 6 months. People say that they grow rapidly, but i wonder how many of you have honestly had them in your tanks?? Mine has grown maybe an inch and a half since the purchase, and no hes not stunted. I wouldnt honestly reccomend puting him into your exact tank because your tank already sounds pretty stocked, but if you get one that is relativly small, like 4-6 inches he would fit in there fine for a while. And btw i might be wrong but arent a RBTS and a red tailled shark very much alike?? Oh and also, the clowns will get large, but once again you do have time, there not going to be 14" in a matter of weeks.... more like years just make sure that they dont appear to be to big for your tank and if they do work on a new home, trust your own judgement on them, and you'll know when they are too big
Jay