I have two male uros and they have been housed together for over 8 years and have not shown aggression. Recently one had a medical emergency and had to have surgery. They have been separated for 3 weeks and I was given the ok by the vet to reintroduce them. I just reintroduced them once so far and it did not go well. The one who had surgery was very aggressive and the "play date" lasted a couple of minutes and I had to return them to their separate enclosures. Any advice on this process or how long it might take? Or will they never get along again?