My cat is jealous of new cat, hisses at me. How to stop aggression?

I would try a Feliway spray, diffuser or collar. It is a pheromone that helps with relaxation and anxiety. There are also supplements for anxiety. Set up separate areas for feeding and two litter boxes so they each have their own space with an area that they both have access to. Usually over time they will adjust if left alone. If she’s still aggressive there are prescription medications to give her for a little while to help her adjust so please discuss this with your veterinarian. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Kaji.

Unfortunately it's going to take time. That said, there are a few things you can make sure of to help reduce stress, especially in a four-cat household (which is a lot!). Making sure each cat has their own space where they can eat, drink, play, observe, etc without the other cats bothering them can help reduce territorial disputes over these items. Pheromone collars and plug-ins (Feliway) can also be placed on stressed out individuals, or in shared rooms (since everyone seems to be stressed) to help reduce inter-cat aggression. Making sure to have at least one litter box per cat will also help reduce stress and competition over them, and reduce the chances of accidents elsewhere. Otherwise, continued slow introduction of the cats is best. If anyone starts to get agitated or too excited, removing them to let everyone calm down and settle back in is best. Continued aggression and upset may also need a trainer or veterinary behaviorist's help. That said, if your home is very small, four cats may just be too much for everyone to get comfortable.

Here is a great article on introducing a new cat to the household. https://www.petcoach.co/article/5-steps-to-introducing-your-cat-to-a-new-feline/ You might want to back up a few steps and try to start the introduction over from the beginning. The second thing you can try is to help Fiona deal with the anxiety of the new kitten by using Feliway, which is a cat pheromone that can be calming. It is available in a diffuser that is plugged into an outlet and is great for a room in the home. It is also available as a spray, which can be used on towels, or the most common locations Fiona likes to spend time. 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 If these do not help, you might consider discussing prescription medication for anxiety with your veterinarian. Thanks for using PetCoach.

Well, Smickle IS king of the house! Actually just let him hiss away. Eventually the hissing will stop. This can take a good few weeks. Some day they will sleep on the same bed, but when they see you, will hiss anyway. Give him as much love as you used to, and make extra time for cat number two. Not every cat learns to love another cat, however almost all cats can learn to live in the same household. So Smickle is jealous now, but if you can manage to put lots of lovings on him, he will forgive you for bringing in another kitty, into his kingdom, and eventually the two will likely get along. It will take time and you cannot force it.

I suggest you try some Feliway diffusers and some environmental enrichment for them. You can refer to the links below. Feliway is like "happy cat" pheromones and really helps to calm cats down. You need to replace the diffusers every 30 days. There are many ways to do environmental enrichment. You can refer to the links below or do some additional research. ( https://www.feliway.com/ca_en/Products/FELIWAY-CLASSIC-Diffuser ) ( thedrakecenter.com/materials/environmental-enrichment-indoor-cats ) ( https://www.youtube.com/watch?v=AejmrLa_Cs4 ) If these things don't work then you should talk to your vet about getting some behavior modification medication for them (like Prozac). Hope this helps. Best wishes.

It does take time for the existing cat to get used to a new addition to the house, and I recommend introducing them slowly to each other. Take the kitten, and put her in her own room with her own food, water, and litter box. Keep the door closed, and for a few days, feed them both treats on other side of door so they associate each other's smell with a good experience. Then let the other cat in the kitten's room while the kitten is in a cat carrier. They can smell each other, but not be in contact. If either becomes upset or show signs of aggression, remove the second cat from the room, and try again later. Praise them when they interact appropriately. When they are interacting well with each other through the carrier, you can let the kitten out of her room, and see how she interacts with the other cat. Praise them when they interact appropriately, and separate them with any sign of aggression or upset. I would get a cat tree with lots of shelves to give the cats vertical space to get away from each other. I would keep the kitten in her room when you go out until they are comfortable with each other.

Introducing a new cat into a household can be very stressful. Cats do not try to act masculine, but another person can certainly change the dynamic of any relationship. I would recommend finding ways to decrease stress in the house. One option for decreasing stress is to add a Feliway Diffuser ( https://www.feliway.com/us#redirected ) to your house. This is a calming pheromone that will work for a month and may be beneficial for both cats. I have also had luck with Rescue Remedy ( http://www.bachflower.com/rescue-remedy-pet/ ) which can be added to the water. Again, this may be beneficial for both cats. If Bear continues to hiss and growl despite these additions, it may be time to take him to your veterinarian for a physical exam and discussion about possible anti-anxiety medication. Good luck! I hope that was helpful. Thanks for using PetCoach.