My two cats were rescued together as kittens (they are sisters) - we rescued them together because the lady who fostered them said they were inseparable. For the first few years they groomed each other, slept together in the same bed and got on really well.
Fast forward to now - they are 10 years old and seem to hate each other. We have daily hissing, fights and even horrible yowling at each other. They are still very affectionate with us and my son, they have always been attention-seeking and a bit clingy if we are home and that hasn't changed at all.
We've separated their food bowls and litter trays and we've started letting them out in shifts so that they are not on top of each other all the time, but it's not helping. Is there anything else that we can try or are they just getting more cantankerous as they get older?