Although the friendly household Shih Tzu loves to hang out with other dogs or cats, some other breeds are not so friendly with other dogs.
On the other hand, a large dog may injure the Shih Tzu during innocent roughhousing.
However, some large dogs do well with small dogs and often defer to their leadership. You must know your big dog very well before taking that risk, and supervision is extremely important.
Shih Tzus normally gets along with other small dogs, especially other Shih Tzu, as long as the other dog is friendly, too. Even so, the bottom line is your Shih Tzu would rather spend time with you than anyone else.
If you leave your Shih Tzu alone for too long, it can cause behavioral problems.
Nonetheless, Some household Shih Tzu may chase small animals like ferrets, hamsters, rabbits, or birds. Others ignore these animals completely or try to make friends.
Be sure your home situation is safe for your new Shih Tzu, as well as for your other pets before bringing a Shih Tzu home.