cat on cat violence

So today, my mom and I went into a pet smart and she just found this one cat she adored. We decided to get her and she seems to be very calm and tame. The worst part of this story is that we already have a cant and she is typically calm. She does nothing but sleep all the time but when we brought the new cat in she just went wild and started hizzing at her! is there anyway to get them to warm up to eachother more? They both are roughly 1 year old and they are both females.

My cats were very hostile toward each other at first. Now they just kind of avoid each other. That's probably what will happen over time.

You forcibly inserted a strange cat into another cat's territory. Of course the original cat is going to be pissed. I'm surprised that you (or your mom) as a cat owner don't know this already. Either of two things is going to happen: 1. The new cat will submit to the old cat (or more unlikely, the old cat will submit), and they will tolerate each other's presence when it is convenient for them, or... 2. The new cat will be rejected by the old cat and depending on it's violence threshold, could pose a risk to the new cat's health. Keep an eye on them for the first week, and if they don't show any signs of submission/dominance then you may not be able to get them used to one another. Some cats just don't get along, and the battle for territory is ever-lasting.Zeviander

sorry when it comes to owning cats we are pretty much noobs =(

Anyways as an update Dot (the old cat) and the new cat (we havent thought of a name yet) are both laying underneath my moms bed. Earlier if dot even saw her she would freak out and hizz but now they are both calmly laying down under the bed looking at eachother and not making a sound. Is this a good sign?