Platys Fighting Help Please.

[Fastblur]

A friend of mine got into the fishkeeping thing recently and got himself some platys. He asked me whether I knew of any instances of such a fish being territorial and fighting one another. As I get what little fishy knowledge I have from here I thought I'd ask you lot.
OK, two platys one slightly larger than the other, and according to him it looks as though the 'red one' is attempting to play tag with the 'white one.' They're in a tank with some smaller fish (guppies IIRC) who aren't being bothered aside from the occasionally platy zooming past.
I thought it might be because one is female and the other male but according to the platy thread having a pointy rearward fin signifies a male platy.
So I'm not sure what to tell him and he seems pretty worried as the pursued fish is getting severely stressed.
Both fish were bought as a pair and got on for about a week of tank life but in the past two days have been chasing one another.
Any ideas?

I don't know how urgent an emergency has to be but I think this might be one.

 

[WILDER]

Ratio is 2 females to a male, i would ask in the livebearer section, they know far more over there, good luck.

 

[Fastblur]

Ratio is 2 females to a male, i would ask in the livebearer section, they know far more over there, good luck.

He doesn't have any more room for more fish, so he's going to take one back to the Lfs. Should he take back the dominant one or the passive one?

(cheers again Wilder. This must be the lord knows how many query of mine you've answered- though this is mine by proxy)

 

[WILDER]

I would take them both back as they don't like being on there own.

 

[Fastblur]

What if one was replaced by two females?

 

[WILDER]

Loads of fry every month and if there is no room in the tank, to be honest i wouldn't get females.

 

[Fastblur]

Ah, I don't know what he'll say but I'm guessing his platy adventure ends here.
Ta for the help.

 

[Fastblur]

Just a sort of update, he hasn't been able to take the fish back yet, but apparently they seem to have declared some sort of peace. With one half of the tank being platy A's and the other B.'s I don't think that'll last though but he's going to give it another day or two to see what happens.

 

[WILDER]

ok.