I adopted 2 males, Astro & Lucky (both neutered) 6 months ago from a farm. They were living in a barn with 16 other cats and all got along well (males & females, all fixed). They have been vetted, shots, etc, all clean health. They are both very sweet, however Astro is declawed and very shy. When I 1st brought them home, they had proper introductions to my resident cats (all fixed females), and Lucky is more dominant natured, but gets along fine with the rest. Astro hid completely for the 1st month, only coming out at night to eat, use the litter box, get petted, etc. (We jokingly referred to him as the "vampire cat") After about 2 months, he started coming out more, some during the day hours, being more social. He's very sweet, and purrs loudly when rubbing your legs or getting petted.
I have 2 female littermates, Charlie & Ruby, (fixed) who are 1 yr old, who I've had since they were 8 weeks. They were here for 6 months prior to the males, and I had 2 fixed female older cats, Lara & Daphne, before them. They all got along fine. Charlie is mild natured & a bit lazy, and Ruby is cute & sweet, but high strung with lots of energy.
About 2 months ago, Ruby (1yr) had decided to routinely bother Astro (4 yrs). (This is how she plays with her sister, Charlie.) Being the shy skittish cat that Astro is, he runs & hides from her, usually under the couch, bed or behind the chair. She will stalk him relentlessly, pounce & chase, until he is cornered, at which point he lashes out at her in fear. There is hissing, swatting, yowling & growling between them both. I have been interrupting this process every time I see Ruby begin to stalk him. Generally she will leave him alone, unless she spots him, then does an intimidation stare, until he runs, then chases. If he doesn't run, she doesn't chase. (MOSTLY he runs. Only doesn't if she's far enough away or I interrupt her sneak up). Back into hiding he goes.
It has gotten so bad for Astro, that he will not come out to even eat at feeding time. I've been bringing his food to him, just to make sure he eats something. He has been vomiting after eating occasionally because of the stress. He stopped going to the water bowl. I had to move the feeding area closer to the living room where his hiding spots are, and he will only get a drink if I stand over him. He will drink for a long time because he is so thirsty. He has always used (sneaked to) the litter box since I had him up until 6 days ago. I caught him squatting in the floor, but took him to the litterbox before he went. He still peed on the carpet later that evening. I've been literally carrying him to the box periodically. The next day, he pooped under the couch in his hiding spot where he sleeps! Then under my bed, then under the couch again. These are the areas where he hides.
I have tried to build up Astro's confidence by playing with him more, and it has seemed to help some. He will now move around the house a little more on his own as long as someone is present, but has not helped with the hiding spots or the litter box issue. I have had them in the room together and played with them both together w/o confrontation. I have used treats to associate a positive experience between them. I have used calming sprays & catnip. Toys to distract Ruby from her intimidation stare. Astro is so stressed out by her, that he hides if he hears the bell on her collar!
I have thought about separation, but I feel that it is avoiding the problem & won't solve it. I was trying to let them work it out on their own, but is not happening. Forcing them to be around each other is hard because of Astro's fear level. I've thought about reintroduction, but not sure I could even get Astro to participate. I worry because Astro is declawed, Ruby is not. Astro has had quite a few scratches on his nose & ears because of her.
My thoughts are A) Ruby is trying to play with him in a cat & mouse game that Astro is misunderstanding, B) Ruby is being territorial and keeping Astro confined to one space. C) Astro is showing fear aggression toward Ruby when she is trying to play & possibly marking his spots to keep her away.
I do not want to rehome either one of them! Ruby is my 10 yr old son's & Astro is my husbands favorite! Any thought about why this may be happening or any advice would be greatly appreciated!