Even if your cat or dog is very friendly, carefree and happy, it will be important to test how they will react to having a cat or dog in the house as a new member of the family before you go ahead and make any changes.
If you already have a Tzu and are thinking about getting a cat, you will want to have at least 3 visits to test how they react to each other. It is best if the last visit can be inside of your home to test how your current pet will react to a new member on their own turf. This is the same if you currently have a cat and want to bring a dog into your home.
What to Look For
While we all wish that our cat and Shih Tzu will become best friends (and some do) it is important to remember that this is not true in all cases...And it is best to prepare yourself for the most likely outcome: That they will ignore each other.
When they ignore each other and both go about their own business, this is a good sign...It means that neither sees the other as a threat.
One must remember that with a small Shih Tzu, some cats can be just as large if not a larger size. If a fight breaks out, both animals can get injured...The dog will not always win in this case.
When the 2 are first introduced, it is best to have the Tzu on a harness - NOT a leash - Using a leash is not a good idea, because if you must quickly bring your Tzu back to you, a quick jerking motion on the leash can put too much strain on the dog collar and cause a collapsed trachea....So especially for times like this, you will want to use a dog harness made for small breed dogs.
Allow the 2 to sniff around and walk near each other. If your Tzu is behaving, certainly give praise. The #1 thing to look for is if they are staring at each other...This is a sign that they may be getting ready to attack each other! If the dog growls, the cat hisses or if either is crouched down and staring, removed them from each other, putting them into different rooms. This will let you know that it is not such a good idea to mix the dog and the cat.