Balloon Belly Molly keeps giving birth

[Jackss]

Hello, I have 2 ten gallon tanks, in one I have 2 female balloon belly mollies and a rubber mouth pleco, and in the other i have balloon belly babies and 2 mystery snails. In the tank with the two females there seems to be something interesting happening. While i have had one of the mollies (Scarlet) for 2 months and i have had the other molly (Raven) for only 2 weeks, Scarlet keeps giving birth. She gave birth to one single baby in late January, then a week later to another 12. I thought this was all but a week ago she gave birth to another 3 and today another 2. So, that's about 17 in the span of almost 2 months. How is this possible as she has no male to impregnate her anymore and she is just continuously pregnant ? Any help would be appreciated.

 

[Essjay]

Are you seeing her give birth to these fry or finding them later? Could it be that the ones found later than the others have been in hiding?

Female mollies and other livebearers can store sperm and use it to fertilise eggs so they continue to have batches of fry for months even though there's no male in the tank.

 

[GaryE]

Livebearers in her family have sperm packets, which will be preserved inside the female to refertilize her for several batches.

Balloon fish are intentionally bred to have a genetic disease of the spine, which gives them that shape. A healthy molly will have very large broods of fry, but I imagine it's the health problems that are keeping the numbers low. Balloon fish are one of the cruel shames in the business side of the hobby, as people buying them don't realize what has been done to them. So maybe the small number of fry is a blessing.

 

[emeraldking]

Yes, this is normal. Like already been mentioned by other members overhere, females of ovoviviparous livebearers can store sperm packets in the folds of the fallopian tube for over a year. This can result in multiple pregnancies, depending of how many folds will be randomly opened by the female to fertilize her eggs.
Like GaryE has already stated, the body shape of a balloon molly can be of influence of the number of fry born. Although, I do have to say, that I've already watched a balloon molly female give birth to 40 fry in one day. But that's an exception.
It's not that such balloon mollies are superfetative. That such a female has broods in a certain time window, has got to do with the amount of nutrition in each egg. The ones with more nutrition in it, will take care of fry that will be born sooner. The eggs with less nutrition, will be born later. Providing eggs of nutrition happens by the female herself before the eggs are fertilized. This is called pre-fertilization.