You need to supervise the first meeting of cats.
Using FELIWAY® during this first introduction is advised to help the cats feel safe and secure. Plug in a FELIWAY® Diffuser a few days before introducing the new cat and use it for at least one month to help both the new and resident cat(s) adjust.
Plug the FELIWAY® Diffuser in the room your cats spend most of their time. If cats are separated or do not share the same living areas, you may need a Diffuser in each area. One Diffuser covers up to 700 sq. ft.
Additionally, each cat should have access to their own resources (food and water bowl, litter box, resting area). See our advice on how to make your home cat friendly, to help avoid potential conflict issues.
When you see your cats face rubbing or sleeping close together then you know that they are comfortable with each other.
You want your cats to get along, and this should be done gradually. While the new cat is restricted to one room in the home, you can swap scents between the cats so they get used to each other before meeting for the first time.
Scent swapping can be done either swapping their bedding or by rubbing soft material on their cheek and placing it with the other cat.
This will allow them time to get used to each other's scents before meeting for the first time.
When the diffuser ran out Tisha got more stressed and started marking again. I went to the vet...