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Why is my new cat's behavior changing after a bad introduction?

Updated On September 23rd, 2025

Pet's info: Cat | Mixed Breed | Female | spayed | 5 months and 4 days old | 10 lbs

Hi my brother just addopted a 9 month old male cat like 4 days ago, and i adopted a 5 mlonth old female cat the same day. We wanted to introduce them so we put his cat inside a keetle/cage but he panicked like crazy. The following day his got alot of symptoms. And since then he has no gotten better, he is a total different cat. His symptoms are meowing alot, fearful, overeating, running away alot, very anyisocial,sleeping A LOT, only lets people at home pet him for like 30 seconds and then pushe

1 Answer

Most Helpful Answer

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Answered By Dr. Melanie, BVSc MS

Veterinarian

Published on January 2nd, 2017

Moving into a new home is very stressful to a young cat, and it's understandable that he's going to be frightened, want to hide, and act antisocial. Add an additional cat into the situation, and that's going to cause him more stress. I would separate the cats, and put the male in his own room to introduce him to the house and the other cat slowly. Make sure he has his own food, water, and litter box. Keep the door closed, and for a few days, feed both cats 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 male 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 male out of his room, and see how he 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 male in his room when you go out until they are comfortable with each other.

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