Join Date: Aug 2012
Location: Minneapolis, Minnesota
I've noticed that it's hard to predict how girls will act in a larger group based on their individual personalities. The fish I thought would be the most submissive in my sorority actually have ended up as the alphas in my tank, and they're also the smallest!
Of the 6 girls I put in my sorority, I only had to remove one and it wasn't because she was being aggressive. It was because she was depressed and mopey and I could tell she just hated it. So that is something to watch for too.
Also, the initial nipping should be the worst of the conflicts, resolving within about 24-48. During this time, check on the fish regularly. Especially for the first few hours, make sure you're checking in every 15 minutes. If you are seeing big fights or injuries after the first two days, you may have a fish that is too aggressive for group living.
Keep a turkey baster on hand - it is really great for breaking up tiffs that seem to be getting intense. Just squirt water towards the fish and they will separate. Of course, the fish need to establish their pecking order so don't use it every time they meet up, just if it looks like one fish is really picking on another.
Pay attention at feeding time too - I had a scare with one of my girls the other day because she ate up all the food in a bid for dominance, got seriously bloated and wasn't well for a day. She has recovered fine, but now I'm more careful to distribute food right in front of each fish and counting exactly how much they're eating.
I do not recommend waiting in between adding girls to the tank; you don't one any one fish thinking they own a section of the tank and getting super territorial over it as more fish are added. Most people prefer adding the fish that seem the most docile/submissive first so they have a chance to hide, but go ahead and plop them in one right after another.
It's also a good idea to time the sorority adding in the late afternoon, so they have a few hours of daylight but then plenty of darkness to rest in. When they can't see each other, it's much harder for them to fight and get stressed out.
Edit: Just realized you already added them, so disregard my advice about that!