My 2 cats not getting along

Question
QUESTION: Hello, I have a female cat, Nikki, who is 10 years old (neutered and declawed) and I have a male cat, sammy (neutered and declawed), who is 7 years old.  I had Nikki first and 7 years ago I acquired sammy as he was a stray and only approx. 4 months old. Sammy had frost bite in his tail, and he was starving.  I kept him in another room away from Nikki while I  nursed him better.  Once he was healthy, I introduced the two.  The have gotten along the entire time, laying in a small bed together with one paw on the other, they have been best friends for 7 years until the last few days.  For some reason they fight, scream at each other, it's terrible.  If Nikki gets near sammy he starts growling already.  I'm not sure if Sammy is the one starting these fights or Nikki is.  Nikki's tail gets really big and they cat fight.  Yet this morning when I woke up, both Nikki and Sammy were laying side by side at the end of my bed, once I got up, Sammy jumped down and later when I went to feed them, Nikki was in the kitchen, I was carrying sammy up to the kitchen, he saw Nikki and right away started growling at her.  I have no idea why after all these years they now seem to hate each other.  Any ideas as to what I can do to get them to stop fighting and go back to the way they were???

ANSWER: Carmen,

There are many reasons that this could be happening. The two cats may have seen something outside that caused anxiety, anger, fear or frustration. What has changed in the environment? Did you recently move? Add another person or animal to the family? Did you recently lose a member of the family? Have they been checked over by the vet? Sometimes if one cat has been recently hospitalized the other will react poorly when they come home. Cats hate any kind of change in their lives, they will often respond with some sort of behavior that is uncharacteristic of them.
My first suggestion is to have them checked by the vet to ensure that they are both still healthy. Next I would do some detective work. Is there a sound or smell that is present in the environment when this fighting happens? I once fostered a cat that got aggressive every time a kitchen timer went off. It may not seem important to you, but you will often see what is causing the problem by watching the cats closely. What is the trigger? What is different in their environment leading up to and immediately following the outburst? Any small change, even if it isn't something that you think is relevant can affect your kitty's behaviour.
Because this situation has the potential to escalate and become dangerous relatively quickly I would also suggest that you separate the two cats if this continues for much longer, that is a precaution that is for their safety and yours. DON'T intervene in a cat fight with bare hands! You will need bandages and possibly stitches if you do. Use a spray bottle filled with water or even a glass of water to dampen their resolve to fight. It will help to separate the cats safely and cool the situation off. You should also ask your vet if this could be something treated temporarily with anti anxiety drugs for both. Sometimes medications can be useful as tools in a behavior modification program. Watch body language very carefully, see what leads up to the fight...It could be very important information to help you, your vet and possibly if necessary an animal behaviorist solve this problem before it becomes a habitual response.
I hope that I was able to offer some help. If you have any further questions or concerns, please do not hesitate to contact me.

---------- FOLLOW-UP ----------

QUESTION: Hi Ali,
Thank you for your quick response to my question.  Since one of their beds is by the back sliding door, and has been for ages, you think that if they saw something outside such as another cat or a raccoon or a skunk that it would affect their attitude towards each other? Hmmm, that seems strange.  Nothing in their environment has changed, we haven't moved, and we haven't added another person or animal to the family.  The only thing that has changed is that I had a 3rd cat his name was Gizmo and he was 20 years old.  In the last few years all he did was sleep in his bed upstairs in the spare bedroom.  He would only come downstairs to eat and go to the litter box, sometimes he would go on the floor.  Sammy didn't get along well with Gizmo the few times they encountered each other sammy would hiss at him and Gizmo would retreat.  Nikki on the other hand did get along with Gizmo, but since he always kept to himself and never mingled with the other two I didn't think they would even notice him gone.  I had to put Gizmo down on Aug. 15 of this year.  So it's been 2.5 months since Gizmo hasn't been there.  I would have thought if it had something to do with Gizmo it would have happened sooner.  
Last night when I got home, I got Nikki and Sammy together because I was giving them treats, which they love.  I thought that if they spend some time close together they will stop being mad at each other.  They were ok together while eating their treats, but after that, when Nikki would come close to Sammy, he would start growling at her again.  Do you think it's possible that Sammy may have a tumour and that could be doing something to his brain? Do vets have something to check for that??  

Thanks again!
Carmen

Answer
Carmen,

Veterinary medicine has advanced to the point where you can do almost anything for animals that you can do for people. When did the fighting start? The suggestion that they may have seen some wildlife or even another neighborhood cat could explain the sudden change in how they feel about each other. As I suggested before I think that it would be a good idea to take your 2 cats to the vet and have a thorough work up done, just to rule out any medical reasons for this behavior. I would be careful handing out cookies and affection when they are being aggressive with each other, you could unintentionally end up rewarding bad behavior. If your vet finds nothing wrong with your kitties he/she may be able to offer some behavioral counseling in office or even a referral to a behaviorist. I think that it would be in your best interests as well as your cats' best interests to get to the root of the problem sooner rather than later. If the cats did see something in the window that is aggravating them putting a temporary frosted film on the offending window is a good solution to help them work through their issues. The films that I am talking about come in a variety of designs and price ranges and they are available at your local hardware store. Good luck in the detective work to solve this case of aggression. I will say that it seems odd that cats who have lived together for 7 years would suddenly become aggressive towards each other, that is why I am suggesting getting your vet involved. If you have any further questions or you need help with anything else, please do not hesitate to contact me.