Cornish Rex spraying after new cat: what helped

Spraying that starts immediately after a new cat arrives is almost always a territorial stress response — your Cornish Rex is telling you the social balance in the house has shifted and he doesn't feel secure. Cat anxiety is genuinely easy to underestimate because cats are so good at masking it, and by the time spraying starts, the stress has usually been building for a while. The most effective calming products for this exact situation are pheromone-based, but the type matters — a standard Feliway Classic diffuser helps with general anxiety, but multi-cat tension needs something different. Before I point you toward the right product, a couple of quick questions: how long ago did the third cat arrive, and how are the cats interacting — are there active confrontations, or is it more avoidance and tension? And is your Rex spraying in one spot or in multiple locations around the house?

That pattern makes complete sense. The staring and avoidance without direct fighting is classic covert tension — neither cat feels confident enough to escalate, but your Rex absolutely doesn't feel safe. The front door and sofa spots are telling too: he's marking the boundaries of what he considers his core territory. Six weeks in, with no improvement on its own, this isn't going to resolve without some help. What I'd recommend is the Feliway MultiCat Diffuser Starter Kit. It's specifically formulated for exactly this — multi-cat households where social friction is causing stress behaviours. It releases a synthetic version of the feline appeasing pheromone, which is different from the Feliway Classic formula and is designed to reduce tension between cats rather than just soothe an individual one. Plug it in the room where the cats spend the most time together, not near the spray sites specifically. One diffuser covers about 70 square metres, and most people see a noticeable reduction in spraying within two to four weeks.

It's a common instinct, but no — and this is where a lot of people go wrong with these products. The diffuser works by reducing the underlying anxiety, not by masking or deterring the spray sites. Placing it near the sofa or front door won't speed things up and wastes coverage in a spot that's less useful. You want it in the shared social space — living room is usually ideal — where both cats are present and where the pheromone can influence how they feel about each other. For the actual spray sites, clean them thoroughly with an enzymatic cleaner like Simple Solution or Bio-one first. If residual scent remains, it acts as a cue for him to top it up. Clean the site, diffuser in the shared room — that combination gives you the best chance of stopping this within a month.

Yes — a few practical things that genuinely make a difference alongside the diffuser. First, resources: make sure you have at least three of everything — litter trays, feeding stations, water bowls, and ideally three resting spots at different heights. When cats have to share, tension spikes even if they're not visibly fighting over things. Second, vertical space matters a lot for Cornish Rexes specifically; they're active and curious, and having high shelves or a tall cat tree gives the cats a way to create distance without confrontation. Third, don't force interaction — let the cats manage their own proximity. The MultiCat diffuser works best when the environment is also set up to reduce competition. If you're not seeing improvement after four weeks on the diffuser, it's worth a vet check to rule out any underlying medical cause for the spraying, but in a case like yours — clear trigger, clear timing — I'd expect a good response to the environmental approach.

You're on the right track. The fact that there's no actual fighting is genuinely a good sign — the hierarchy just hasn't settled yet, and your Rex needs reassurance that his space is still his. The MultiCat diffuser does that job well when it's placed correctly. Give it the full four weeks before judging whether it's working, and remember to replace the refill on time so there's no gap in coverage. Good luck — Cornish Rexes are usually sociable enough that this does resolve once the stress level drops.