Here is how I see it. Because you live with your mother I would wait it out or call the landlord to see what animals are permissable without a 25 dollar charge. If there are charges for every animal, including ones in tanks, I would wait until I was out on my own. Yes snakes are easy to hide especially in a rack system, but I would only take that risk if I wasn't endangering anyone but myself. You don't need to bring your mother into an eviction if it comes to that.

Best thing to do is call the landlord and hear what he/she has to say.

Good luck.