Short answer: the key to a successful introduction is not letting the cats meet face to face right away — spending at least a week in separate spaces, getting used to each other through scent and sound first, makes all the difference.
How should I set up the separate room?
Give the new cat their own dedicated room fully equipped with a litter box, water bowl, food bowl, and hideout, and let them live with a closed door between them and the resident cat for now.
What does the 7-day schedule look like?
① Days 1–2: the new cat settles into the separate room and gets used to the new space itself ② Days 3–4: swap blankets or bedding between the cats so they get familiar with each other's scent ③ Days 5–6: indirect interaction through the door, like feeding with a hand slipped underneath ④ Day 7 onward: crack the door open for brief visual contact. Take it slow through these steps in order.
Does hissing or defensive behavior mean it's failing?
Not at all. Some initial hissing or wariness is a completely normal reaction. That said, if the reaction stays intense and doesn't ease up, it's worth slowing down before moving to the next stage.
When should I start letting them see each other face to face?
If there's no strong rejection during the scent-swapping stage, it's safer to start with short glimpses through a slightly open door and gradually extend the time.
What if the introduction just isn't working even after a while?
If severe aggression continues even after several weeks, don't force it — slow the pace down, or consider consulting a behaviorist for an approach tailored to your specific situation.
