Cats suddenly not getting on

[Stopthatknocking]

We have 2 cats, approximately 5 years old.
They were in a foster home together and had to be housed together as they got on so well.
They came here1 year ago, and 1 was very nervous, but finally came around.
They got on so well, sat together, groomed each other and generally were lovely.
But in the last month or so they have begun fighting.
The more confident of the two has started overgrooming, and the vet said it is stress.
She seems to be bullying the other, but it's the 'bully's is the one overgrooming.

I have tried plug in Feliway, been promised it works.
But it's having no effect.
We leave all the doors in the house open, so I wondered if the feliway is just too dilute in the air space?

Does anyone have ideas to stop this bullying and overgrooming?
Thanks

Feliway really did work on my nervous cat (had no effect on the always confident one) but we did have to use more than one to allow for the space in the room.

I think this may be the issue. But they are really expensive!

I wish I could work out what trigered all this aggression.

Do they go outside? If not, do they have enough resources in the house - litter trays, food bowls, water bowls, beds, scratch posts etc?

We didn't have to use Feliway permanently - just a few weeks and things seemed to settle down.

They have their own litter trays, opposite corners of the room, and I started feeding them separately since the vet suggested it last week.
I habe noticed the bully trying to get the food of the other one.
I used to just fill the bowls and leave them to graze all day. Now I feed them, stand and supervise and then remove the leftovers when they have finished.

They don't go outside, they do have their own beds but usually sleep on my bed.

We try to play with them, but they are not that interested. They usually play with their toys at night.

The recommended number of trays is one per cat, plus one extra, so I would try and increase the number of trays you have - maybe even have four so they can each poo and pee in separate trays.

Most issues with stress in cats are territorial and are often resolved with outdoor access - a catio or a cat-proofed garden could be an option if you don't want them to roam.

One cat would be OK outside, the other I'd worry about.
The rescue advised they stay as indoor cats.
I could get more litter trays, but one always poos oh the floor anyway, even if she has a fresh unused tray. And I won't be able to move around my house with 4 trays!

Hi OP, maybe try a different Feliway? There are several types, perhaps a different one would be more effective? We have 7 cats, 1 unrelated, 1 from original mother and 5 from direct descendants of original mother - we use Feliway upstairs and downstairs on a permanent basis since we had to rehome MIL's cat (one of our original kittens)

If one is already pooing on the floor that's a clear sign of stress to me, sorry 😞

Lots of cats just aren't suited to life inside - can you cat-proof your garden or install a catio for them?

I totally get not wanting them to roam or feeling like they wouldn't be safe outdoors.

Is there another cat in the neighbourhood upsetting them. My indoor cats, would turn on each other when an intruder was in their garden.

A friend has these for her cats since one eats much more slowly than the other. They’re a bit expensive but might solve the food part of the problem?
https://closerpets.co.uk/collections/microchip-cat-feeder

Thanks everyone for your advice.

I'll keep going with the feliway, keep feeding them separately, get another litter tray, and consider letting one of them go outside.
The other was a stray for many years before the rescue had her, so I don't want her going awol again.