Male guppies attacking others. Help!

[Michelle1980]

I decided it was time to separate my female and male fancy guppies for obvious reasons. Some I had at work and some I had at home. I set up a 30 gallon here at work and first put in all the males (6) I had here at work. Everyone got along great. So I brought in 5 from my house and these little monsters are just unbelievable. They are terrorizing the original males. Chasing them, nipping at them. It got to the point I had to separate them and the 5 more aggressive guppies from my house went in my 10 gallon with a beta, they seam fine in there. No nipped fins, no attacking each other.

So today I got some of my platys (2 adults and 2 babies) from home and brought them here to work. 2 male guppies got in the net and let me tell you, netting those platys was harder then I thought, so when the guppies got in the net I was not about to risk losing those platys.

I bring them here to work, float the bag, and some stress coat, waiting 15 minutes and let every one in the bag out. At first one platy was jetting all over but now, 5 hours later is looking better and everyone else looks great. But those two male guppies are terrorizing the other male guppies! What gives? I know the whole dominance thing could be at play but at home, where they came from, they were in a community tank, (40 gallon) with patties, other guppies, some tetras, cat fish, and some mollies. I never had a problem with them at home.

My only choice I guess is get a bigger tank for the aggressive guppies and beta or bring them back home. I don’t understand.