Female cat suddenly becoming dominant

[tigerfit]

I have a behavior issue that is getting worse, don't know how to stop it.
My partner and I have 5 cats since moving in together a year agoz. 4 were his, one mine. Mine is a young 2 yr old female literally adopted by my chihuahua as a tiny abandoned kitten. Never around other cats until the move. Partner has 16 yr old declawed male & female, and 7 yr old brother and sister rescues not declawed. All are fixed.
My female, Chloe, is skittish and keeps to herself, mostly on her tower I brought with me. She has slowly begun to tolerate being around all the others EXCEPT the 7 yr old female. Formerly shy herself, she started chasing Chloe. Chasing escalated to attacking whenever she catches Chloe off her tower. Now she has also begun being bullying and dominant to the other cats, mostly her brother and the 16 yr old female.
Me breaking up the fights does not seem to be helping. She just waits til I'm out of the room and starts back. Chloe will not fight back unless cornered, she runs. But she cannot just walk around the room without being attacked.
What else can I do?

 

[yayi]

A sudden change of behavior is usually a sign of illness. When was the last check up of the 7 year old aggressive female? 

 

[tigerfit]

I did try that first since she was due for shots. Nothing found out of the ordinary with a regular exam. Of course she was super sweet to all the techs, so their opinion is she does not have a physical/mental issue.

 

[tigerfit]

I ordered one of the Feliway diffusers. Reading the reviews, I'm hoping this might help the aggression, as well as a few other issues that may be stress related ......the senior cat's random howling, and the 7 yr old male spraying (that has been neutered since a kitten!)

 

[ashley berner]

Good luck! I've had the diffuser plugged in for about a week now... not sure if it's helping, or just what I've been doing to try to correct my cat's behavior.