Aggression towards younger household cat

[Jessica & Pumpkin]

Pumpkin is 12 years old and was diagnosed with diabetes about 8 months ago. She has been on ProZinc and a different diet with good results. However, in the past month or so, she has been increasingly aggressive towards one of our other cats. Jasper is 4 years old. She was not happy when we took him in as a kitten, but she did adjust and they usually just kept their distance. We have another male cat, Fritz, who is also 12 years old and he and Pumpkin have been together most of their lives. They get along well and are bonded like brother and sister.

Recently, Jasper can just be standing at the doorway trying to decide if he wants to come in the same room with Pumpkin and she will growl. If he doesn't turn around, she charges at him and it can turn into a fight. I really don't think he is antagonizing her. It's usually that he just wants to be in the same room my husband and I are. Shortly after he leaves, she is relaxed and purring again. Jasper recently had some UTI issues and the vet suggested that it could be stress related. He is wearing a pheromone collar and we have installed a couple of Feliway diffusers in the house. I am beginning to think that Pumpkin may be a stressor in addition to changes in routine with stay at home orders. I feel sorry for both of them and I'm not sure what to do. I am not sure why she would start to be so aggressive towards him now. I am probably going to get her a pheromone collar as well. If she gets out of hand, I will separate her and put her in a room by herself to calm down. I don't know if that really helps. Does anyone have any other insights or suggestions?

 

[jt and trouble (GA)]

I watch that animal planet show "My Cat From Hell" and most of the stories (like yours) are quite interesting. One episode two bonded cats were sitting in a window sill watching the world go by, when all of a sudden a truck backfired. It made a big boom and one of the cats ran away. It was "ON" (this was all caught on video) after that, the two bonded cats couldnt be in the same room together, without striking out. There were other like stories as well. Of course I am not saying thats whats happening in your house. Just sayin that the strangest things can happen, to just turn a household upside down. Jackson said that the one cat lost his confidence and it caused the other to lash out. How strange their little worlds are!

 

[Noah & me (GA)]

We've been crammed in here at one time with nine cats and a dog and not a care in the world. Now we have five and some of them just barely tolerate each other but when we're not watching the big bully stops all his annoying behavior. We need to get some motion activated cameras here.
Our Jasper has been gone a long time but I've always loved that name. Good luck.

 

[Panic]

I read one time that using treats worked with introducing new kitties, so I tried it the last two times we got new a kitten. I found that the older cats adapted MUCH more quickly than they usually did with a new face. Any time the older cat saw the newer one and was about to throw a fit, they got a treat.