Yes, this.
If they are still actively getting into fights, they should not be together. Put one of them in a separate room. Put a screen or baby gate in the doorway, so they can see & smell each other, but not get together to fight. (They could still fight through the gate, but either has the option to end it by moving away.)
I had to re-introduce my former cat, Baxter (RIP) to the crazed princess (Pandora), because one morning she heard something that scared her, saw him, and thought he had done it. Seriously weird, but, as my vet said, “She’s a drama queen and her brain is the size of a walnut.” (Both true statements.)
First, get multi-cat Feliway and put it in all rooms. It won’t be cheap, but it is worth it. Keeps my little crazed princess calmer.
Second, go back to step one of the introductions that others have mentioned. Great advice above! I love the idea of using mesh baby gates, it’s perfect. My brother is quite handy, and just puts a screen door in one of the rooms. Whatever works.
When you re-introduce, do it in small steps, and give treats frequently, whether food or special toys.
If anyone starts growling, distract them immediately. I used each cat’s favorite toy (the Da Bird and the laser pointer). Mine learned that they could fight, or they could have the good toys.
If they are getting along, give each cat a treat.
Then, before anyone gets cranky, separate them.
Keep up the interactive time and treats. As you progress, you can leave them on their own a little, but keep an eye on them. Keep a squirt bottle around so that if any fights start, you can squirt them (it’ll make them separate).
It took about six weeks to totally get them all calmed down, and Pandora had lived with Baxter all her life!
Thanks for the suggestions. I may give it another go.
About how long does a Feliway refill last?
Mina’s claws are small and difficult to cut. Declawing isn’t possible here. Are there protectors which could be slipped on?
Yes, there are actually little tips that you can put (or have your vet) put on a cat’s claws. They don’t last forever, but some people prefer them to claw clipping.
About a month.
Has anyone tried calming collars like this: https://www.amazon.ca/SENTRY-Calming-Collar-Cats-Pack/dp/B0026JAKWG/ref=pd_sim_199_5?_encoding=UTF8&psc=1&refRID=T4YWAXNH8FRAT7V76JM6