Hi
Depending on the temps and feeding they can definitely
mature in under two months!! In that small a volume of water it may take a while longer.. You'll have to keep a very close eye on the development but I have found by the time I can tell the difference it's too late lol
I keep them in my outdoor ponds for that reason as the local bird population helps thin them out but still i must have several thousand easiy.lol
have never found a way to keep them from breeding.
gary

The warmer the temps the quicker the development, but it's gonna be several weeks before gender differences become discernible. You could always donate fish to the school's science department.

OK Gary, are you saying I would need a magnifying glass!
It's been 1 month now, do you think if I get close enough I can tell? OMG, that's why I bought 3 females!!! Unfortunately, I live in NJ so placing them in a pond would probably not be a good idea!!! Do fish stores buy them? I read somewhere in cyberspace, they would have to be at least 1" for them to take them. I would feel terrible if I have to flush them... There are still around 4 in the main tank with the adults and they are still alive! Quick little buggers. Thanks for your response. I hope I can tell them apart better than you!

Hi
My point was that when you can tell them apart it is usually too late.. In smaller tanks the development will be much slower but have found they can reproduce under 1 inch in length. I would say 3 months tops at tropical temps.
They are all born female .actually neuter but the gonopodium develops from the anal fin .It is very obvious even with an unaided eye.
I occasionally trade some to LFS but also use some as live food for angels and discus. Naturally the stores will want larger bright colored ones.
gary

I have currently about 15 fry neon redtail moon platys, 3 different batchs/births so they range in age and size.. is color a way to determine the sexes? Some are still a clear gray/silver and others same batch already have color, also, isn't more slender the male and more "pot bellied" female? Glad that is only in fish and not us human females btw!!, anyway, am butting into the conversation as have had same questions.

hi
To the best of my knowledge there are around 700 recognized varieties of platies ,swordtails..So color is no indication of anything. When the differences you mention are seen thet are already sexually mature. They are all born neuter as I mentioned but the anal fin develops into the gonopodium. The male copulatory organ. In females it remains fan shaped. With swords of course the male also develops the caudal extention. Hybrids between the two may or may not develop this.
Have heard rumors that they can actually change sex but have no first hand observation of that. So keeping all of one sex may or may not work.
The fry that have the best color are those you wanrt to keep. i raise red wag swords and have noted that those that are pink at birth will become the brightest red. I'm not familiar with the strain you mention but red came from the platy side of the cross so would probably work the same way.
I keep mine in outdoor pools so firsthand observation is almost impossible.
gary

I had a couple of fry fish that were females after a couple of months when I could tell by their fin. However, after a while, two of them turned into males so they can change sex.

i've just bought some female platys and some are about to have
their babies and i went to a local pet shop . the other day and i ask the helper how long does it take for the female to have her babies and he said it takes about three week for her to have her fry .and for me to remove her from the tank cause the males will pick at her until she passes away. what i am really asking does anybody know really how long it takes for her to have the fry . if so please let me know it
would really help me .cause i've already have her in a breeder.but she isn't doing nothing.

Getsation is about a month. But by the time you recognize things, it will likely be less. When she is squared off, as opposed to rounded, and you can see the babies' eyes, it won't be long.