cats arguing/being chased by younger cat

[4catsownme]

KC and Kalli (girls), Kanga and Fin (boys). Kanga and Fin moved in when i moved in last October, ever since then KC and Kalli have got on with Fin, but Kanga seems to look for trouble and scare the girls. the girls growl, hiss get scared and get up as high as possible to get away from Kanga. This is now upsetting my partner as the girls are hers initially and she hates the idea of them being scared in their own home and not enjoying the freedom they were used to. Is there anything you could suggest that may help? we feed them at different levels, given the girls somewhere safe to sleep and the boys have their own space to sleep and go out most of the time.
KC and Kalli are sisters aged 9
Fin is 3 legged aged 8
Kanga is 2 and a half.

Kanga and Fin get on. as they are initially mine.

[meriad]

I'm assuming all four are neutered / spayed? Do they have outdoor access or are they all house cats?

You may need to go back to the beginnings with Kanga, and start the reintroduction process for him. Ie confine to a room and do a gradual scent exchange etc; but I suspect Kanga is just being a boisterous typical teen cat that is actually looking for someone to play with and get rid of excess energy, but the girls aren't interested and don't understand. Do you engage in play with Kanga? Something like a Dabird is marvellous and may shift the focus of Kanga's attentions

[Crewella]

I suspect Ria may be right and he's just trying to play - from your description it doesn't sound like aggression? It might help to go through introductions again - the Cat Chat help section has good advice:

http://www.catchat.org/hierarchies.html

I currently have 5 cats and my youngest, Daz, sometimes terrorises the only girl who is an elderly lady and doesn't appreciate the rough and tumble. He likes to chase her, and unfortunately she tends to run, which makes it worse (as soon as he 'catches' her he loses interest and wanders off). Just a thought, but when we first got Daz and discovered this issue I then adopted a younger female who adored Daz and became the playmate he so desperately wanted - old Nellie's life became peaceful again. Sadly we lost Peaches to a road accident last year and Daz, when bored, is back to wanting to chase poor Grumpy Nellie. I am considering adding another younger female to the group, but am waiting for the right cat to come along as she will also need to fit in with the rest of the gang and needs to be a quiet, unflappable, sociable sort of cat (which Peaches was). It's a hard call, but sometimes, just sometimes, adding another cat can balance out a multi-cat household.

[Jacks]

I agree with Crewella that this is a difficult one - you can rarely predict how dynamics will change in multi-cat households when things change or you add or subtract a member. And the relationships between each cat and the others can be totally different. I have five and there is some enmity between two; a big boy and the smallest girl, but it's manageable because we have a distinct 'boss' - an alpha female who keeps the boy in order and provides the glue that keeps everyone in their place and happy. When number 5 arrived, a young but mature female, she provided something of a challenge and it took the two of them a year to really find their place with each other - but now they are fine.

After a year with the problems between your boy and your girls things are not going to change quickly any time soon, but it sounds like you're handling it pretty well and it's a long-term project (like my boy and girl). After 18 months she has stopped freaking out whenever he's near, but he'll still chase her if she runs, and if he stops and stares at her too long she'll start growling and hissing with fear and eventually (if I don't distract him) she'll bolt and then that puts us back a step, but these days not for long. The more positive (non-confrontational) times they have the better. Bit by bit they'll learn that he's not going to hurt them. The problem is that fear is the most primal of responses, so it's the hardest to work with.

And yes, you need to provide a lot of active play - like catching the feather (daBird) for a two year old - he's absolutely in his prime.

I hope you can get things sorted out in the long term.