The only two fish in the tank the fry were born in are balloon mollies and corydoras, and the mollies have been in the tank well over a month and they are both female so I was pretty confident they weren't molly babies. How are you so sure the fry is a molly? Due to there not being visual barbels? The tank I found them in had floating plants but I put them in The new 10 gals for a grow out tank, I have a week old guppy fry in the tank as well but they seem to be around the top and middle of the tank compared to the newer babies? Also, I have seen many breeders have bare bottom fry tanks due to it being easy to clean out uneaten food etc. It is also far easier to spot them without a substrate. I could see how no definite bottom could stress the fry though, is this a must? for they will be moved to bigger planted tanks once they have grown. Thank you so much I look forward to you're reply.