Hi, I have not heard of a week old ball py being 18 inches. Are you sure it is just a baby? So far the only thing I have heard is that a 20 gallon is ample size. Also to add on that, I pretty much bought a bigger tank cause I found a deal and was just gonna save it as a treat for when the snake became large enough for it. The snake's personality will tell you if it will enjoy a longer trip to the water dish and more room to feed....


Thanks,

Mi.