Assuming it is a girl and doesn't get really large, a 40 gallon breeder could work but of course bigger the better to a point. You got to remember, you need to be able to keep correct heat and humidity and the bigger the cage, the more work it is to keep that. But bottom line, a male or normal size female can live in a 40 gallon breeder. Extra large females will need something bigger. Now for my advice, next time you go to upgrade the tank, check out PVC/HDPE cages and go for one of those. They are more designed for snakes and keep heat/humidity and snake inside better.