whiteskirt tetras

[fishwatcher]

I have 3 whiteskirts. I originally had just 2 and they got along ok, but I'd read where there should be at least 3 of them, so I got another one. Well, now they all constantly harrass each other, chasing and nipping any time one sees the other one. I wonder if I should take them all out and put them in a separate tank for just a little while, change the regular tank around some then add them all at the same time. Would that help them not be so nippy? I don't have room for any more of them, as you can see. What should I do?
I have noticed that the one with the least flowy tail is the meanest one. Is this a male or female? They seem to have taken territories too, but only bc the meanest one is making them, it seems.
Is this normla??

 

[fishwatcher]

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