I kept a RTC in a 180 for 6 years. He grew to 30" and was quite happy. He was healthy and quite a personal pet. I built him a 2500 gallon indoor pond and he didnt grow but 2" bigger in 2 years. Didnt swim around much either, even at night Has anyone really grown a 4' RTC in a simple house pond or tank ??? I'd like to see some pics. I've seen a few 4 footers in my day, but thats not the norm in captivity.
I also think too many people power feed the crap out of these fish. They grow fast but not 24" in a year like some say. With normal feeding mine tend to grow about an inch or so a month.