What size tank should my snake be in? Currently, he is in a 20 gal. He is five years old, but only 2'6" (I don't know why, I have only had him for a month, he came with all of the supplies) should I upgrade him to a bigger tank, if so, what size? I have heard if they are too big, the snakes can feel insecure, but I don't know if that is true.