I am a new owner of a humane society rescue chihuahua that turned out to have a liver shunt. I have seemingly 'controlled' this by diet and pills. My problem is that I have another chihuhua (both females) . They play together but suddenly it turns into a snarling teeth baring clash. I do not want either to get hurt so I break it up usually with a loud noise. I am afraid to leave them alone together if I leave the house temporarily. One does not seem any more of less dominant. My heart is with my original chihuahua but I want the newbie to work out, too. There has never been any blood. Mostly just horrific noise and posturing. What to do?