Why is my cat acting aggressive and stressed since we got a new cat?

Unfortunately the new cat is likely causing stress and this is a common feeling reaction to stress. She may not want to go outside as long as that other cat is around. It may be difficult to keep the other cat out of your area unless you want to purchase or build a fence. There are fences available that have curvature to the top that make it difficult for a cat to climb over. There are some things you can do at home that can help to manage her stress. Set aside 30 minutes a day for a vigorous play. Use a pheromone diffuser. There is a special prescription food made by Royal Canin called calm which may help. Use food puzzles. Give environmental enrichment. Lastly, your veterinarian has medications which can help as well. Many cats require a combination of therapies. Best of luck.

The multi cat diffuser may give you slightly better results but they both will likely help. The diffusers are nice because it’s a constant infusion of the pheromone that occurs even when you are not home. Other things that can help Trixie to feel more calm are to provide climbing opportunities that satisfy her natural instincts. A tall cat tree or shelves mounted to the wall with a bed on top can help some cats feel more secure. Set aside 30 minutes a day for vigorous play as tiring her out may result in less anxiety. Royal Canin also makes a diet called Calm that affects the serotonin levels in the brain and some cats do very well on this diet. If she continues not to do well, medications may help. I hope this is helpful and please feel free to post any additional questions!

As a starting point, make sure that both of your cats have been neutered, as intact male cats will often spray urine due to hormone influences. If both cats have been neutered, the spraying behavior is likely a sign of stress and anxiety, but medical causes of inappropriate urination should be ruled out by a visit to the veterinarian. Separating the newly adopted cat and only allowing the cats to interact under direct supervision may minimize fighting behavior. Also, utilizing calming pheromone products for both cats, such as the Comfort Zone® Multi-Cat Diffuser, may decrease the stress level for both cats. If the aggression continues, consultation with a specialist in [veterinary behavior](http://www.dacvb.org/) to get to the root of the aggression, coupled with prescription anti-anxiety medication may be helpful for both cats.

Moving can be very stressful on any species. Cats will sometimes display signs of mis-directed aggression when they are stressed. I would recommend getting Feliway pheromones started asap. These come as plug in diffusers or even collars if the cats will tolerate them. They release calming hormones into the air that people won't smell, but do help relax agitate pets. Give the cats a safe place to retreat to - a room or hideout where they can get away from each other, the dog and people. If possible try to have items from their last home there (a bed or toys). Try to feed the same food, switching it over gradually. I would recommend having several litter boxes in different areas of the house while they are acclimating. If the fights are serious enough you may need to separate the cats into separate areas of the house and gradually reintroduce them to each other. If the behaviours continue or worsen, I would recommend consulting with their veterinarian. There are medications that can help in conjunction with training to decrease behavior problems. The following website has some great information about cat behavior by one of best behavior veterinarians there ever was. You may want to search for articles on aggression and anxiety in cats for some more ideas. https://drsophiayin.com/resources/cat_behavior/

Thanks for using Petco Pet Education Center, formerly Petcoach! This is possibly because she smells differently. I recommend a product called Feliway which can help decrease stress and anxiety associated with environmental changes and stressors. You may find this online or at your local pet store. It usually works great in this type of scenarios. Good luck and have a great day!

Here is an article on introducing new cats to the home. https://www.petcoach.co/article/5-steps-to-introducing-your-cat-to-a-new-feline/ In addition, I recommend a calming pheromone such as Feliway that can help with anxiety. It is available as a plug-in room diffuser for large areas, and as a spray for small areas like a mat or bed. https://www.drsfostersmith.com/product/prod_display.cfm?pcatid=8906 https://www.drsfostersmith.com/product/prod_display.cfm?pcatid=37241 Another product I like is Composure, which is available as a little treat. https://www.petco.com/shop/en/petcostore/product/vetri-science-composure-feline-bite-sized-chews I hope this helps. Thanks for using PetCoach.

Change in environment can be very stressful for animals so I am not surprised that he is having some problems adjusting. You could try a Feliway diffuser and some Solliquin chews and see if that helps. https://www.feliway.com/us#redirected http://www.solliquin.com/#page-top