In the book, " The New Natural Cat," Anitra Frazier STRONGLY suggests that we should let the cats work things out on their own. Only intervene if there is REAL fighting. One thing that she recommends, that is REALLY hard to do, it have nothing to do with the new cat, until she is accepted by the cats already in the house. Of course, feed the kitty, and make sure she is OK. And of she hides, let her. Who knows how she was treated in her other home??? We have brought MANY new cats/kittens into our house, and eventually, they work things out....GOOD LUCK!!! I think Oliva is a great name for your new baby! Is she eating and using the litter box?