platies (Xiphophorus maculatus hybrid)

Question
How long are the pregnant. What is their gestation time. Is there anything that increases or decreases this time.
I have a birthing holding tank ready and I need to know when I need to put "mommy" in it. Thank you.

Answer
Hi Karla.  What a great choice. I breed these guys too.  Gestation time is 28-35 days. They will get to the point where they look like they are going to literally pop (you get used to it after the first time or 2). They also tend to "square off" and look like a box in the back-end right before they have them.  They may also stop eating, or hide, sometimes both. You can see a change in them, that's for sure.  Most of the time it's subtle, but a change nonetheless.  When they are close to the due time, you can try doing a partial water change and then slowly raising the temperature about 2 degrees.  Sometimes that can help them along. Not always though.

You want to try to put the mom in the birthing place about 3-5 days prior to your feeling like she is ready to have them, so she has time to settle down. If not, you run the risk of her aborting them.  I haven't had it happen to me too much, but you always wind up with a couple or few egg sacs, which is no big deal.  As she is having them, if she is not in a breeding trap, try to offer her bits of food to try to keep her from eating the fry, which she will.  It's just nature that she does. Giving bits of food helps keep her full so she won't be so interested in eating them, but it doesn't always work.  Just be sure you take her out soon after you think she is done having them. (Can take anywhere from 1-8+ hours) I like using a breeding trap because the fry fall through to the bottom and she cannot get to them unless the come back up on their own, then what I do is i remove her from that into a net to keep her away from the rest of the fish for about 24 hours so she can have a rest. It's hard work on them and if you put them right back in the tank with males, they may badger her to the point where she dies. I only had that happen once and I won't let it happen again!  They definately need a rest though....it's hard work for them!!

The fry need sparkling clean water all the time. I use a sponge filter in my fry tank and do a 30% water change every 3rd day.  I also feed my fry freshly hatched brine shrimp, or if I don't have any available I use frozen brine shrimp and frozen daphnia for them.  It helps them grow. They all grow at different rates too.  You might want to "cull" them as you see abnormalities right from the beginning.  Culling is weeding out the fish with problems (i.e. crooked bodies, not able to swim right, misformed, etc.), anything that isn't a perfect fish.  It's a lot less heartache when they are little as opposed to when they start getting bigger, I don't know why, but it is. You will also have some (not always, but most of the time) that don't make it.  That's normal too.  If you ever get to the point where you are over-run with them (I have approximately 200 right now ranging from 4 months down to 1 week), you can let the mothers have the fry in the regular tank and let nature take its course. It's "survival of the fittest".  If they make it, they deserve to!  If they <gulp> get eaten, chances are you would have culled them anyway.  It's just nature's way of population control.  I have plenty that have managed to make it in my main tank, I was actually surprised by the amount that did!!

I can go on endlessly about this stuff, but I won't.  If you need anymore help, just write me back along the way. I also invite you to join a forum called "Everything Aquatic", which is a great new place to go and ask all your fish related questions absolutely free, ask for advice about tank situations, opinions, tell fish stories, anything you'd like. Everyone chips in to help everyone else out.  We are just starting to build this forum, but I expect that its going to be great! You can reach it at: http://groups.msn.com/EverythingAquatic/   I am an assistant manager there, and I go by the nickname of "MrsCrabs".  Feel free to introduce yourself if you decide to join, and mention that you met me through here. A fantastic website full of GREAT information can also be found at:  http://www.americanaquariumproducts.com/index.html   To the right side you will see "Aquarium Information". Through there you can get to countless articles full of up to date information about everything you can think of.

Best of luck to you!  Again, if you should need any help along the way, find me and I'll be happy to assist you!