I've been planning on getting a bearded dragon for a while but I won't be out of dorms until next semester. There is a 10-gallon tank rule but the recommendation for baby bearded dragons is 20 gallons. Would it be a bad idea to get a baby bearded dragon and keep it in a 10-gallon tank for a few months until I move out? I'm planning on getting a 40-gallon tank or larger once I do move.
I would wait until you move out to get th beardie. 10 gallons is much to small, as is 20 gallons. Many people start off with a 20g, but I would reccomend skipping that and getting a 40g as your first tank. There's no point in spending money on two tanks.
The "start small and then upgrade" is a clever little scam by the pet shops If you feel the 40g is too big to start, you can simply block part of it off with cardboard.
depending on the amount of room you have you should just go with the larger tank, they grow up pretty fast. if your hell bent on getting him early though just get the 20 long and he'll be ok for a few months. keep a good eye out for tank deals while you have him though, that way you can snatch up a good priced one early.
A 10g tank would be perfect for a leopard gecko instead, they are crepuscular so more likely to be active when you are around. They also require less attention than a beardie I find. However they have a longer life span so be prepared for up to 20 years