Baby fish?

Question
Ok I have 2 sunburst platies and one really red dark orange one, i'm not too sure what it's called but they can all breed together, two are girls and one is a boy. About a month ago, one of my fish (I think the sunburst girl) had A baby, all I could find was one. I researched a little bit on the fish because i'm no expert and I think I remember it saying they have about 20-150 fry, so I thought ok maybe she just had a low amount of fry and the rest got eaten so I let it go. A few days ago I think the dark orange girl had A baby also only one. Are they sick, are they gettin eaten, am i just over looking things, could it be the male fishes fault that theres only one? BUT im also not sure if he's even the father because I recently got these fish a couple months ago and their my first fish ever so I really dont want to mess things up, maybe when I got them from the store they were already pregnant, so i dunno if it even has anything to do with the other male platy. Oh and one more thing the baby from a month ago and the baby from yesterday, I put them in the same small tank (i have a big and a small one) and I was wondering if anything could go wrong. I do think their both girls but the other one might be too small for my eyes to tell and the 1 month old fish keeps sort of poking the 1 day old fish with it's tail while swimming backwards. I was wondering if you knew what this means. I was trying to find answers and it lead me to this page. I hope you can help me figure these things out. If not thanks for your time anyhow =]  

Answer
Good evening Erika, thank you for your question.

It's indeed possible your platies had more fry than one, and the rest are getting eaten. To encourage more fry, it would be best to separate your pregnant females into a separate tank and let them give birth in there, then immediately remove them. I don't recommend folks use breeding traps, but if you do intend to use one, then the net kind are the way to go, so that the tank's own water circulates inside it.

Another thing you could try is keeping the females well fed with favorites like frozen bloodworms and frozen brine shrimp. The mothers are voraciously hungry after giving birth. Although you could see it as a form of population control. Don't encourage more fry than you can keep or trade in! This would create its own kind of problem. Have you checked out this site on livebearer reproduction?
http://www.fishforever.co.uk/livebearers.html

The fry should be fed several times a day, 4 times or up to 6 times is recommended. You can feed finely crushed flakes, prepared foods such as Hikari First Bites, or you can make your own foods such as hatched brine shrimp or the inside of a hard boiled egg yolk. Just take the yellow of the egg out and shake it vigorously in a cup with a bit of water. Feed the fry the crushed cooked egg yolk using a turkey baster. The protein helps them grow! Fry foods are especially messy, so change as much water as you can. When I was raising my cichlid fry I did a 20% water change daily. I recommend changing this much water at least every three days.

It sounds like you are observing playing or aggression between the older fry and the new fry. Either way it's a good idea just to keep an eye on them and to keep the tank well fed. If you can, leave a romaine lettuce leaf in the tank so they have something to pick at at all times. (Romaine is more nutritious than most other kinds of lettuce.) Of course, you'll have to replace it frequently.

I suppose what could go wrong is the older fry could pick on the new fry. You could try adding lots of cover in the way of plastic plants (or real ones, like hornwort) so that the fry will have a place to hide. Mostly, it's just important to keep the water quality up. Oh! One more thing. If you are using a filter, make sure the intake doesn't suck up the new fry. You can put a piece of stocking over it, or switch to a sponge filter or box filter, a gentler kind of filtration.

Overall, I believe your platies will eventually produce more fry at a time, and perhaps with your intervention more will be saved - you may even find yourself overwhelmed soon!

I hope that helps. Check out these sites for more info:
http://www.wetwebmedia.com/FWSubWebIndex/platyreprofaqs.htm
http://www.practicalfishkeeping.co.uk/pfk/pages/show_article.php?article_id=25
http://www.aquaticcommunity.com/breeding/raisingfry.php

Take care, and best of luck to you.
Nicole