I have two Male cats who are 10 yrs. of age. They have both been fixed/neutered/spayed?. Whichever is for Males.
Anyway, they get into this vicious fights which have been happening more and more as of late. Also, they seem to be occurring late at night, usually after ten PM, but they also occur during the day. I guess it's the nightly fights that really affect me as I have to get up early the next morning.
First of all,
why do they fight with each other? I notice one cat will stick his paw at the other and that will initiate a fight sometimes.
And I know they are not playing because there is intense tail-wagging and lots of hissing/growling going on along with fur on the ground afterward. However so far, no blood drawn.
I usually yell and separate them when they fight. Or if it is a lot of fighting, I will spray them with a water bottle.

I hate doing this, but it's my last resort.
At night I have no option.
Both cats
HATE closed doors and will whine and scratch at any closed door which would mean = no sleep for me either.
Please help.
I don't think they have any health issues. They eat and use their litter boxes normally.