my 3 month old fry are just starting to look like real fish now, but I still can't tell what sex they are. They're only half an inch long, and their sibs that were born about 3 weeks ago are starting to catch up with the older fry. How do I make these babies grow faster? they have their own 10 gallon tank (i plan on giving most of them away cuz i have 15 fry), its always at about 78F, and I do 50% bi-weekly water changes and full water change twice a month, parameters are always at a stable 7pH, 0 ammonia, 0 nitrite, nitrate is 0.8.