I'd say their growth is on par with a rtc in most cases although some would argue that some rtc still grow faster. Expect him to be between 1'-2' in the first year, 2'-2.5' the second year, 3' or so the 3rd year, and slows way down after that. There are pics of them being pulled out of lakes over 4', and some asian aquariums definitely have some pushing the 100 lbs mark. It's safe to say that in ideal environment should reach 4' within the first 5-10 years of life.