Cats aggression with each other

Question
I adopted 2 cats (ages 2 and 6) from the local shelter in mid-December. I chose these 2 cats because they had lived in the same house prior to going to the shelter and I thought I wouldn't have to worry about them getting along. I was very wrong! Everything seemed to be fine until early January when Jenny (the older cat) started hissing and swatting at Bella. I chalked it up to a little tiff and didn't think anything of it until I realized several days later that the situation had not gotten better. To this day, it still exists, though not every day. But now that Bella has been the recipient of this behavior for the last 2 months or so, she can now become aggressive with Jenny (it seems preemptive to me). A lot of this seems territorial to me, but I have no idea what to do about this. Bella is constantly looking for Jenny to see if she can take the opportunity to use the litter box or get to the water fountain. I feel really badly for her now. Do you have any ideas on how I can get this to stop?

Answer
Denese,

Sometimes in multiple cat households cats can become a bit on the territorial side when resources are not quite adequate in their eyes. I generally recommend that you have as many litter boxes as you have cats, plus one...This eliminates the fights over the litter pan simply because one cat cant be in several different places at once. I have three cats and one water fountain, I make sure to have fresh water available in 3 places so that the cats don't bully one another to establish dominance. I am wondering if there is any way that the cats have seen or heard something outside that frightened or frustrated them. Cats are fairly territorial animals and if a neighborhood cat or wildlife came onto your property when the girls were in the window they may have become upset and since the source of the frustration wasn't accessible to them they chose to take it out on each other. You can change this though. I would recommend that you look at putting removable privacy film onto any windows that the girls have access to on a regular basis. The newer privacy films come in many different designs and the best feature is that they are removable if you choose not to use them permanently. I would also like to suggest that you try a homeopathic remedy called Bach's Rescue Remedy to help settle any anxiety that your girls may be experiencing. Rescue Remedy is a blend of flower essences that tends to have a calming effect on animals. In this case I would suggest a dosage of about 10 drops per day in fresh water each morning. You should start to see a difference within a week or so. You can usually purchase Rescue Remedy at health food/natural health stores. There are other remedies to consider if you find that the Rescue Remedy works well but is not the complete solution to the issues that you are seeing. There are other Bach Remedies that are tailored for specific things like jealousy, anxiety, frustration, etc. That having been said I would suggest that you research these remedies by reading through the charts in the health food store, you may also want to pursue the option of making an appointment with a holistic vet in your area. A holistic vet practices both conventional medicine as well as things like herbal medicine, homeopathy, and in some cases even acupuncture and massage. Hopefully things calm down to a dull roar at your place fairly soon. I do hope that the information I have provided is helpful and useful in terms of beginning to solve the problem that your kitties are having. If you have any further questions or concerns, please do not hesitate to contact me again.