An adult will need a 30 gallon tank. Its better to go bigger though. But that is really the minimum for a snake that size. Hope this helps. Don't forget things like under tank heater, thermometer, things for it to climb on, and a water bowl big enough for him to soak in (makes it easier to shed.) you'll also want a second "feeding tank" if you feed him in the same cage that he lives in he will be aggressive any time you reach your hand in to get him out.