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My cats hate each other after moving. How do I reintroduce them?

Updated On September 23rd, 2025

Pet's info: Cat | Domestic Shorthair | Male | neutered | 10 lbs

I just moved apartments two days ago and my two cats hate each other now. They have lived together for over a year and they’ve never had any issues before this move. I moved about 6 months ago as well and they didn’t have this problem. I am keeping them separated, but every time I open a door to try and integrate them back together, they start hissing and try to fight. They are acting like they’ve never seen each other before. What do I do?

4 Answers

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on September 29th, 2019

Oh no, that's not good! I would separate the cats, and slowly reintroduce them to each other. Take the cat who is aggressive, 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 aggressive cat's room while the aggressive cat 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 aggressive cat 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 cat in her room when you go out until they are comfortable with each other.

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Other Answers

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    Answered By Dr. Heidi DVM, CVA, CCRT, CVTP, CVSMT, CVCH

    Veterinarian, Certified Veterinary Acupuncturist, Certified Canine Rehabilitation Practitioner

    Published on July 10th, 2018

    You did the right thing by separating the cats. What Atreyu displayed is called displaced aggression and is very common in cats. It will be important that the cats are no longer agitated and are acting normally before you consider reintroducing the cats. Do not rush this process. Generally, I will begin by keeping the cats in separate rooms with a door between them, so that they can smell one another through the crack under the door. After a few days of allowing this type of interaction, switch the cats for half an hour so that they are in the other cat’s environment and allowed to explore and smell. Several days later, allow them to see one another through a screen door or wire crate. If these interactions seem positive, eventually allow them to interact in a supervised area, but be sure that both cats have the option of leaving if they become too stressed. I would also consider adding a Feliway Diffuser ( https://www.feliway.com ) or Comfort Zone Diffuser ( https://www.comfortzone.com/ ) to your house to decrease stress. 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. There are a number of companies that make calming treats such as Composure ( https://www.petco.com/shop/en/petcostore/product/vetri-science-composure-feline-bite-sized-chews ). You could also consider calming music specifically for cats ( http://throughadogsear.com/tace/through-a-cats-ear-1-music-for-calming/ ). If you continue to have problems despite a slow, gradual introduction, it may be time to talk to your veterinarian about possible short-term anti-anxiety medication. Good luck! I hope that was helpful. Thanks for using PetCoach.

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    1Pet Parents found this answer helpful

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    Answered By Dr. Melanie, BVSc MS

    Veterinarian

    Published on October 4th, 2019

    I would slowly reintroduce them to each other. Take the cat who is aggressive, 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 aggressive cat's room while the aggressive cat 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 aggressive cat 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 cat in her room when you go out until they are comfortable with each other.

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    1Pet Parents found this answer helpful

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    Answered By Dr. Heidi DVM, CVA, CCRT, CVTP, CVSMT, CVCH

    Veterinarian, Certified Veterinary Acupuncturist, Certified Canine Rehabilitation Practitioner

    Published on March 16th, 2018

    I'm so sorry that you are having this problem. I do think it would be worth separating them and starting over in their introductions since they are having such significant problems. Sometimes, we have to do a slow and gradual introduction to allow the cats time to acclimate to the change. Begin by keeping the cats in separate rooms with a door between them, so that they can smell one another through the crack under the door. It does not matter which cat is in the bedroom. After a few days of allowing this type of interaction, switch the cats for half an hour so that they are in the other cat’s environment and allowed to explore and smell. Several days later, allow them to see one another through a screen door or wire crate. If these interactions seem positive, eventually allow them to interact in a supervised area, but be sure that your submissive cat has the option of leaving if he becomes too stressed. I would also recommend looking at options to decrease stress. 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, that can be beneficial for both cats. If problems continues despite a slow, gradual introduction and one of the above options to decrease stress, it may be time to take the dominant cat 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.

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