Probably couldn't hurt. Just make sure you siphon out anything at the bottom (food & waste) with an air hose or turkey baster. Remove the female after they drop and remove the divider. I found after a few generations my guppies lost interest in eating fry and I eventually stopped using the breeder trap.
yeap thats it but that pic is a male and it looks exaclty like the male i have. it doesnt matter cause there the same species. and yea they were called balloon mollies when i bought them. are females just fat like that or is mine acutally pregnant? becuase now shes hiding behind the filter and shes moving around weird and breathing faster are those signs? i have a breeding cage too but shes not in it.
Even for a balloon molly I would say it is still pretty big. I'm not too familiar with mollies but my guppies would drop soon if they looked like that. HTH.