Swordtail Bully

I have set up my tank and put populated in this order: zebra danios, cory catfish, red wag swordtails, neons, 1 dwarf gouramie. Its been set up for 3 months now, and the neons and gouramie are very recent to the tank & the bullying started before they were put in.

The swordtails, I have 2 females and one male. The male bullys one of the females to a severe degree. Its always the same female he goes for. She tries to hide, and when he finds her plays dead, she's obviously in distress when he chases her. She comes out of hiding when being fed.

Initially, this happened once last week, now its happened three times this week in a row and I'm worried about how long the female will last.

Any ideas?

Its definately a female.

When we initially got the three, I ended up with two males & a female so I had taken one of the males back to the store which I swopped for a female. She's been in the tank for a few months now, it only appears to have been in the past two weeks the bullying has started.