to you for sticking it out Di. I know how difficult it is when cats don't get along. You wonder if things will ever settle. I am not even going to promise you they will because chances are they may not. Kitties got off to a bad start with being sick. It takes a long time to change that.
I think I gave you the website on introducing cats. You may have to retry the intros. This time don't worry about how long it's taking. Cats are perfectly fine in one room. It isn't going to kill them to have one of them separated. Probably the hardest thing for you to do is to decide which one will be separated from everyone else.
Here is the site again if you don't have it any more.
Is it possible Ziggy was taken to the pound before for the exact same behaviour I wonder? It is also a possibility that he was not socialized the proper way when he was a baby. Probably taken from his mom and siblings too early.
Here's a couple of more sites that may help.
Also a blurb from another site.........
Cats who live together will often fight. Usually one cat has to be the dominant cat. Sadly for cat owners, cats do not resign themselves to being the 'underling' or accept that they live with the other cat, so they may as well just get along together. No, they insist on fighting!
The best way to ensure that blood is not spilt is to ensure that each cat has space. Each cat also needs a separate litter tray and a separate one which can be used by either cat.
Try to establish some safe hiding places for each cat, so that they can easily avoid danger. If one cat repeatedly sits in a doorway, move it. This may look innocent but is actually a feline aggressive pose, designed to control who comes in and out of the door.
If one cat appears to be the underling, ensure it has some high resting places where it can feel safe. But try not to get too hung up about it. Sometimes cats just fight to get attention. But, if it becomes very serious then you may have to talk to your vet to see if he can recommend a cat behaviourist.
If all else fails have you thought of a low dosage medication to calm Ziggy if he is the one being the aggressor? Have you noticed if it is him that is starting things or is Zuzu giving off signals? Swatting, staring at Ziggy too much, etc? Ancient Girl and a couple of others have used meds to help calm their kitties. Maybe something like that will help.
to you. It will get better. Thank you for not giving up on them.