I suggest that you come up with a plan and go on the offensive, rather than waiting for them to give you an ultimatum. Offer the compromise that you will stop expanding (that includes no breeding) until you are out of school and on your own financially, as long as you aren't required to get rid of what you have. If they are supporting you, even with tuition, then they have a very strong right to tell you where your money is going to be spent. Tell them that you understand and respect that right, and you had no intention of misleading them in any way. As others have mentioned, you are at a very unstable place in life. Although I doubt you will lose your passion for BPs in just the next couple of years, you have to bear in mind that you will need flexibility when it IS time to move out, find a "real" job (parent-speak for salary and benefits), and having twenty-thirty-ninety snakes will make that a LOT harder, especially since you will still probably need to live with a roommate, who may not share your passion. If your parents are reasonable (I can only advise in how I would have approached mine), then I think they will understand your desire for the hobby, appreciate that you came to them with a plan like an adult, and ease off your back now that the initial panic attack has subsided.