I don't know about the accuracy of saying the bigger the tank, the faster it grows. Snakes grow as fast as they will. Some faster than others even if fed the same amount and same diet. Even in a small tank, a snake will continue to grow. The fallicy of a snake only growing to fit it's container is just that. That said, my new snake who's only 20" is in a 10 gl. My amel who's 31" is in a 20 gl. They both seem perfectly happy with those sizes.