Cat constantly stressed up

Hello!
I hope somebody can give me a piece of advise here cause I'm going insane
I have 2 cats: Mr. Spock, 7, male and Tigrasha, 6, female, both rescued and fixed since they were 3 months old. At the begining they were best friends but that suddenly changed when we moved to another appartment with a backyard and they started to get out. Suddenly Spock can't stand Tigrasha. He turned into grumpy, hissing, growling cat with a low self esteem. My female is not very bright, but cudly and pleasant cat but I sometimes get the feeling he can't stand her stupidity. Anyway, this is going on for 3 years already. He also became agressive towards us. He can lay in my lap and all of a sudden bites and runs away as soon as Tigrasha's entering the room. When my 2 y.o. daughter passes by he can hit her for no reason (and believe me, my kid was taught how to treat cats with respect even before she started crawling). My female never ever attacked him but he hates her guts
The major problem is that our appartment is small and I can't separate them to reintroduce... May be you have suggestions for us? I feel really sorry for him and want to make him happy and relaxed. I tried Basch Flower remedies with no success already.
I'll appreciate any tip!

Tiggy you might want to try what I'm trying with my Missy. We just started it yesterday and so far its not worked but it seems geared to a problem like yours. I bought this from the vet but it is available online. It's a Feliway electric Diffuser and works somewhat like a Glade Plug-in. It diffuses synthetic feline facial pheremones and supposedly creates a state of well-being and calm. It says that it enables reactions to stressful situation to be controlled and avoided. Supposedly useful in the following situations: moving to a new home, visits to the vet and return from hospitalizations, adoption, rearrangement of furniture, vacation homes, new arrivals and overcrowding. I have used the word supposedly here because I can't say yet that it works and the vet also had not used it for his cats so couldn't confirm that it works.

Hi there-

I have used the Feliway Comfort Zone Room Mister and it does work. But there could be a lot of reasons why Spock is lashing out suddenly. He could be the type of cat that now wants to be outside all the time- does he lash out at her when they are outdoors? It could also be that at night when you are asleep strays and ferals visit, spray your trees and leaves, and then depart, working Spock into a state of frenzy. You can neutralize your backyard by spraying vinegar around the grounds if you know where they are spraying, or even if they are visiting. Sometimes lashing out is a result of the cat not feeling well- when was the last vet visit? Also if you don't want the ferals and strays in your backyard, and you are not leaving food out for them at night, then you can make a visit to your beauty salon and ask them for a baggie of human hair. Sprinkle the hair around your backyard, and unless it rains, the scent will keep ferals off your property.

Others will have ideas about the aggression-did you check out this link?

http://www.thecatsite.com/forums/sho...threadid=20837

I'll try to find Feliway Comfort Zone, but it may be a bit difficult (I live in Israel and not US).
Hissy, I read your reply and I think you are right about Spock. He really prefers outdoors now and Tigrasha is more of an indoor cat. When they are together outside they are playing as if they are best friends.
Our backyard is not exactly "ours". It belongs to the entire building, it's just that we are living on a ground floor and leave our window open for cats to get in and out. There are lots of ferrals hanging around and Spock is frequently fighting with them. That's our situation