My 4 y/o Yorkie, Lexi, was not welcomed by my 2 older Shih Tzu when I brought her home as a puppy. They would never play with her. Besides Lexi, I have just my lovely 14 y/o Tzu now (my 15 y/o had to be put down this past January).
Riley, the Yorkie puppy came home about 3 weeks ago & my Tzu just basically ignores him, except when he gets in her face barking & she will growl & snap. I found coins in a soda can has almost eliminated Riley doing this. He barks & jumps at my Tzu & Lexi whenever he tries to engage them in playing which has not worked.
My problem is my 4 y/o Yorkie, Lexi, who has been very spoiled by us as she loves to be loved, cuddled & made over, which my Tzu never really did. We love that as much as Lexi does. I know she hasn't received as much attention since Riley arrived as he does require my attention more to teach him. I do strive to give Lexi as much attention as I possibly can. She is first for feeding, etc. She had basically ignored Riley & stayed away from him. However, the past several days she has started fierce growling like I have never seen her do & showing her teeth & snapping at when Riley when he gets close to me, but only at certain times. I shout No! Stop! This gets Riley barking & jumping at her. I immediately remove Lexi & isolate her in the bathroom, gated off, for a period of time. She immediately stops the behavior once I have her out of the room. Most times this works, but other times it will start all over again once she is allowed to return with us, i.e. in bed at night or on the sofa with us.
I am so scared that she will attack Riley & really hurt him. She has never been this way with any other animal. Riley is only 2#; Lexi is 7.5#. Am I handling this correctly? Is there something else I should be doing? Will just being consistent with what I am currently doing stop this behavior? I would certainly appreciate any advice/suggestions you may have.
This behavior has broken my heart as I love my Lexi soooo much. She is my little girl & I adore her. One night she didn't get to sleep with me all night & that is the first time ever.

I had decided to get Riley for Lexi to have a companion as I realize my Tzu will not be with us forever. I had hoped Lexi & Riley would eventually become playmates/friends. I love Riley so much & can't stand the thought of him possibly being hurt.