I've had Dcat for 8 yrs since she was tiny. I did have another older cat at the time but he is no longer with us. We have a visiting cat who is very laid back, they generally ignore each other but do have a sniff occasionally.
In November, I took in a stray kitten, a few months old. She was ill and very quiet. However as she's got better and grown, the 2 cats are not getting on. Dcat rarely cones down stairs now. It's 50/50 on which cat "starts" . Dcat will sometimes have a go at new cat. Not full on fighting but will walk up abd do the one handed smacking thing.
New cat will sometimes huss and yowl at dcat when she walks past or ambushes her at the bottom of the stairs.
Is there anything I can do to help them settle? New cat isn't going out yet (spayed yesterday). I'm hoping things might improve when she can. I'm having to leave them shut in separate areas atm when I go out.