My cats have suddenly started fighting - why

[Jinglebellsarenearlyhere]

Two Dcats, happily coexist for over two years. Not besties but happy to sleep on the same bed with about a foot between, will eat at the same time etc etc. But recently they have become more seperate and have started boxing each other, running each other out of rooms etc. What's going on?

I take it they are both neutered? Are there any possible health concerns that could be making one of them grouchy? It sounds like they have both matured somewhat and they are no longer friends. I think I would leave them to sort it out by themselves unless they start getting into full on fights. Perhaps one has suddenly become more dominant. Maybe set up a couple of snuggly boxes somewhere so they can easily have have their own personal space and hopefully this will blow over but be prepared for this to continue for a long time if they really do not like each other any more.

Has a new chair or cat bed or cat tree or something similar been introduced that they might be competing for?

From your description (boxing, chasing) that sounds more like play to me than actual fighting. Mine do this for a good half hour or so every morning & evening, then settle down close together very happily. The wrestling on the sofa sessions can look really rough, but I realised there aren't any other signs of them not getting on 100% perfectly otherwise.

If there's no hissing, growling or ears flat back, there's no sign of injuries, and the chasing seems to be roughly even amounts from each, I reckon they are just playing

Thanks all. both neutered, one female, one male. They both have their own special places in the house to sleep and respect that. They both have has fighting injuries on ears that we have noticed but have assumed they were got from fighting mice / other cats, not each other. They both seem a bit reclusive And unsettled but nothing I can put my finger on. Both healthy as have just been to vets for annual jabs and check ups.

I don't think it's playing as neither appear to enjoy it and one or the always escapes. Are there any things I can do to facilitate friendship again?

I'd guess that there's a new cat on the block that has altered the mix of things. They both go outside?