Why would my cats suddenly be fighting with each other?

[Hebburnisaplaceonearth]

They have always got on fine, bar the occasional race round the house and pounce on each other game. Recently they seem to be getting more annoyed with each other- hissing and scrapping a lot. Any ideas why or what I can do about It? Nothing obvious has changed recently...

I'm assuming they're both neutered? (How old and what sexes are they?)

It sounds almost as if there's something else in the mix. Have any eg mean toms been around or near the house? And do they go outside and if so do they use a chip cat flap?

(Sorry for all the questions.)

PS - if they don't go out, I'm wondering whether one or both have too much surplus energy which they need to work off.

They're nearly 6 and nearly 7, both female and spayed a long time ago. Both have free access to outside via a catflap 24/7. Only cat that I ever see is next doors, also female, who they don't like but it has been around for 1 year+. Hmm...

I'll lay a guess that there's a new cat on the block - although it's not impossible that they're getting on each other's nerves. That happens.

Maybe with less a-doing in the garden (eg fewer prey animals around) they're a bit full-of-energy-and-nothing-to-do?

Is your flap a chip one that only allows them inside?

PS - I use 'block' advisedly. Somewhere on their territory - which can be quite extensive for cats, even females.

My mum's boys started scrapping after many happy years together. She got the Feliway plugin at Xmas and they mellowed right out. We even brought my cat to visit (who battered them and taught them all the swear words when they were kittens) and they were all mellow and happy!

Worth a try, I reckon.

Not not a chip one, do you think it should be? We have a dog so was hoping that stopped other cats from coming in here! Will look into feliway thing, thanks