Mine usually got along ok, but my oldest one, didn't like it when I brought in a new one. She is a dachshund, and 10 years old. She is fine now, plays with them all and it keeps her young. It probably took her about a month or less, and she was use to the fact the others were staying. I have 5 dogs total. Candy the dachshund 10years old, then Rocky..Yorkie 6years old, then Rosie..Yorkie 2 1/2 years old, Romeo..Yorkie/Poo 1 1/2 years old, and Raindrop..Yorkie turned 1 on January 4th! What a crew.