circa 23 Nov 2003 10:21:32 -0800, in rec.pets.cats.health+behav,
Danathar (dougb@attglobal.net) said,

When I brought my now-departed Alex into my household, I thought that
it would *never* work out. He was one helluva, um, SPUNKY, cat, and
he was vicious in his attacks on the others. I ended up calling the
humane society at my wits' end and they gave me a very, very good
piece of advice- some cats are more sensitive to change than others,
and it can take them a long time to adjust. They told me to wait
three months, which seemed an eternity to me at the time. In reality,
it probably took a full year for all of the kinks to get ironed out
in Alex's interactions with the other cats and even with me, but I
don't regret putting forth the patience and effort, as he turned out
to be an amazing, loving, beautiful creature who brought me
tremendous happiness.

Battles will happen, and they're a part of how cats establish their
boundaries with each other. Don't try to get in the middle, as you
found out. A squirt bottle works wonders. Give it time.

Laura

Hiya,

I know EXACTLY what you're feeling, but please, do hang in there a bit
more. They adjust to each other on cat time, unfortunately, not on
human time. I introduced two not quite two year old females together,
one I'd had for nine months as a singleton and it literally took 6
weeks until Flower could move about the house unmolested a decent
portion of the time. Now they're working out a timeshare on the
backyard.

I know it's really emotionally disturbing when one cat is really
aggressive towards the other, but honestly, I think it's what they
need to do. At 3 months in, mine do pretty OK most of the time (except
when Flower "breaks the rules" lol), but there's still a spat of some
sort pretty regularly. But they also groom each other sometimes, sleep
peacefully in the same room, share litterboxes and left over food and
cooperate occaisionally on various kinds of mayhem. And I never
thought ANY of that was ever going to happen.

Interfere as little as you can manage. Here are some things you can
try to keep yourself sane. If they seem to be hurting each other, try
a sudden loud clap of the hands to startle them off each other. If you
see them glaring or Whiskers looks ready to launch an attack, try
throwing a ball or a toy in his face for distraction. Give Whiskers
alot of love and one-on-one affection and realize that he's trying to
protect his home and his human from another cat who he fears might try
to take it all over and run him off. Don't act like you particularly
care about Marigold. Act like Whiskers is your cat and Marigold is
someone else's cat who you're feeding and letting stay here. You'll
have plenty of time to nake it up to Marigold later on and actually
she'll be grateful for the lack of attention. Overwhelm Whiskers with
love and attention until he can't stand it and will WANT a respite
from you. And otherwise just let them work it out. Eventually Whiskers
will let Marigold do certain things and be in certain places at
certain times without interference. And slowly over time, she'll get
more "privileges" ....

I'd be surpised if it's still quite as bad in a few months.