PLEASE HELP ME WITH SOME ADVICE!" I'm having a big problem with my two cats and recently adopted third. My first cat Sundai who is 1 year and almost 3 months, and my second cat Mango who has just turned 5 months 5 days ago aren't getting along and I think it's because of my third cat who is a Siamese not currently named, she looks to be about 1 year or a little under. I think Sundai might have had some redirected aggression due to the 3rd cat. When she was in the room with Mango and we let our 3rd cat explore, she smelled her from outside of the door and attacked Mango in the room with her. We separated Mango and Sundai for ten minutes, and put our 3rd cat back in the room, they got along well again and then we let our #3 cat out to re-explore. This time we separated Mango and Sundai into different rooms and when we put #3 back into her room after re-exploring, we let Sundai and Mango out again to reclaim their territory for a little while, Unfortunately when I opened the doors Sundai saw Mango and hissed, I thought that she just could've been startled and didn't fully realize it was just him. That was the complete opposite. She realized it was him and began to chase him around the house and they were screaming and hissing and Mango was scared for his life, Mango escaped and Sundai stopped aggressively pursuing him, and with that moment we put her in her cat cage locked it and put her inside our bedroom. She just fell asleep but when she is up she reacts to every sudden movement I make around the room as if she is ready to protect herself from intruders. I'm very worried that Mango might start getting aggressive because of her 2nd case of Redirected aggression towards him. Also Mango and Sundai are both un-spayed could this be part of the reason at all? At the time I got them I didn't have the finances to spay/neuter them, now I will thanks to some help from an amazing person. PS: Mango and Sundai didn't get along when I got him as a kitten, it took time but it was never as bad as chasing, she would just walk, growl and then run the opposite way. Then as time passed as I introduced them, she treated him like a child and even nursed him and they became closest ever since to a point where my girlfriend took Mango to visit her parents and she would cry until he came back. Now this has happened. I'm totally distressed, and saddened.