[450AHX]

Two weeks ago I got a kitten (Peanuts) from a friend's friend. I'm not too sure about his age, so let's say about 3 months old or so. He's very friendly; he sleeps at the foot of my bed, follows my around the house, and practically purrs just from being in the same room as me.

Since I live alone and I'm away for 7 hours or so each day, I decided to get him a buddy to play with. I brought Smoke, a two month old kitten, home three days ago, and they started off on the wrong foot. Peanuts basically growls, hisses, and/or spits at him whenever Smoke gets close enough, like last night when they both climbed onto the bed, and if they're in the same room for too long, he'll go right over and start a borderline play-fight/fight (they're not hurting each other, but there's some vocalizations here and there, and if one tries to get away, the other doesn't back off).

Now, so far, that's pretty much normal for two cats who are not accustomed to each other yet. The odd thing is that Peanuts gets completely different while either one is eating or drinking. They'll share the same bowl at the same time no problem, even if there's two bowls, and on one occasions I caught Peanuts smelling Smoke's butt and in another licking his ear.

And now for the worrying part. I just came back from the vet because Peanuts had been sleeping all day yesterday and barely eating and drinking. Turns out he had developed a renal obstruction. The vet said in twenty years she had never seen one in such a young cat.

So I'm not sure what to do, partly because I'm not sure what I'm looking at. I'd expect a territorial cat to be even more territorial around food and water; but for him to be friendlier? And the obstruction thing really worries me. If Peanut's going to get so stressed out that it turns into a health issue, perhaps it'd be better to return Smoke to the shelter, maybe get one of his sisters instead.

 

[catloverami]

Did you do a gradual introduction? For kittens that are around 3 mos., they usually don't need a long introduction, but you should make sure they are healthy and have no health issues. Did you have Smoke checked out by a vet? Have both kittens been wormed? had their vaccinations? They really should have been separated at the beginning into separate rooms until you were assured that they were in good shape. Then let them interact; a bit of hissing is normal. Play with them together with a teaser or wand type of toy, and this will help them get over their strangeness to each other. Pet them often and their scents will be mixed together, and everyone should be fine. Enjoy their antics!

 

[450AHX]

Unfortunately, no. I don't have the space for a gradual intro.
The people at the shelter said Smoke was vaccinated and "deparasitated" (literal translation), which I guess means "wormed".
I was told about an hour ago that Peanuts was rescued from an "untrustworthy keeper", so that might have had something to do with it.

 

[catloverami]

It's possible Peanuts was found/rescued as a very young kitten and hasn't learn the proper socialization skills (how to interact with other kitties, control his bite and claws, and kitty body language to show their moods) if he was taken away from his litter mates and momacat too early---before at least 11 wks. So it will likely take him a bit more time to get used to playing with Smoke. In the meantime give Peanuts time to recover from his renal obstruction without being bothered by Smoke. Can you keep him in a separate room until he's feeling better? Bathroom? Switch them between 2 rooms.

 

[450AHX]

Well, so far he's been so lethargic that they haven't had many chances to interact since Saturday. He usually crawls in between the mattresses of the double bed, where there isn't much room for moving around, and pretty much only comes out to use the litter box or be force-fed.
The good news is that he just ate a mouthful of tuna for human consumption (too finicky for cat tuna, I guess), so he's recovering smoothly.