It will max out at around 11-20 feet when fully grown. It all depends on its gender and how often it's being fed, health, etc. They grow relatively quickly and will need a large enclosure when fully grown. I would say yours currently needs a thirty gallon based on the pictures I've seen, but it's really to tell the size in those. Can you send one of him compared to your hand or a yard stick? Do you know his approximate length and weight?