Platy pregnacy

Hey guys,
I was just wondering how long until a Platy becomes pregnant?
A little context:
I have a 15 gallon tank with 6 female platies, as well as a Betta and 5 neon dwarf rainbowfish (no more fish).
I also have a 29 gallon with 4 male platies, and various other community fish.
My question was if I add one of my male platies to my 15 gallon, how long until one of my females is impregnated? I wouldn't keep the fry, and my tank is pretty sparsely planted. I was going to catch a lot of the surviving fry and give them to someone I know who keeps large cichlids (Yay for the food chain!).
So in other words, I want to experiment with breeding.
So can you answer my question and is this a good plan?
Thanks,
Michael

 

It depends on how willing she is. When she is impregnated, she will give birth after around 30 days.

 

Yeah it's around 30 days. Also how heavily stocked is the 29 gallon? I would consider moving the rainbows to the 29 gallon and would have a backup tank for your betta in case it doesn't work out.

 

Yeah I keep his old betta 1 gallon bowl in the basement for emergencies, and the 29 gallon is pretty well stocked, so I don't think it could support the rainbows. And I figured it would come down to the enthusiasm of my females! At least I don't have to worry about him chasing one to death, considering that there is always 5 other females!
Michael

 

You should also take into account that when you buy female platy from the pet shop they are usually housed with males and so will be pregnant when you buy them and they can continue to become pregnant for up to six months after that even if they have not be living with a male.

 

Yeah I thought about that, and I figure, well, let them reproduce! I have someone to give the fry to, and most of them will get eaten or starve to death, because I am not buying them the artemia. It might seem cruel, but I don't want to end up with 6 tanks full of platies, and neither do my parents!
Michael