The large gimpy swimmer boy, is actually swimming more normally. Back end does sink a little, but not as bad. I also added a bubbler, Which distributes heat better while getting them not to be lazy poops ;) He has not flared yet, or bitten anyone, he is one of the gentlest males I've got.
Oh and for those who did not know, one fry decided he wanted to eat a piece of java moss, and it went from his mouth to his gill. We got it out, and it was a tad inflamed, but this fella is lucky I check everyone - even at a 200+ count. He is now jarred and food for him is MONITORED
I have them in what was the community tank (there are still four baby platys in there roughly the same size). That is a 30 gallon regular. So far so good... There is a soft tubed bubbler in the back under the gravel that does give the water a bit of movement.
Most of these fellas are females, with a few males here and there.