Are they 2 males? 2 females? Male/female? If they are 2 males, separate! They will eventualy kill each other. 2 females it COULD work out. However, keep a good eye on them for the first 2 days and keep a good watch on them at night. This is when fighting can start as that is when they are most active. Male female pair, if you dont mind lots of babies in a short amount of time. They will be fine.