[Buggy]

I had a similar problem. I have three black skirt tetras and my husband bought me two painted glass tetras to go with it..one green and one pink. He didn't know about the dying process and how bad it was for the fish. Anyway, the three black skirts used to hang out together but since I put the painted ones in the tank they have all separated and staked out individual territories...each black has a painted between them...and if one crosses the others area they get nipped or chased. I think the natural fish somehow see the dyed ones as being different and "wrong" so they try to get rid of it or at least avoid it, kind of like a pack of dogs will pick on one that is deformed, sick, injured or a runt. It's not natural therefor it is to be eliminated. My best advice is take the dyed fish back to the lfs and get some natural colored ones...about 6 as they are schooling fish. If you like the bright colors try neons, cardinals or diamonds, they all look beautiful in schools. You didn't say how big your tank is so I can't advise how many to get. Post more about your tank and we can go from there.