birth

Question
I have a fresh water aquarium with mollies and guppies. about a month ago over night we had babies and also that night our fish Vera(a fancy tail guppy) died. n now that the babies r older they look like her. so is it possible she died while giving birth, or does she only lay eggs, and died of some other reason??.... every since she had babies weve been getting alot alot of egg sacks on the walls of the tank, but they come and go and no babies, but they other day 2 of the mollies were(for better lack of ways to put it) rubbing side to side, back and forth.(never before seen behavior from any of our fish) n now that fish has a very large stomach and has been laying low to the rocks, and kind of shaking. So is she giving birth or do mollies only lay eggs?? im VERY confused and any sort of information would help, thanks alot and God bless.

Answer
Hi Heather.  You have all "livebearers" in your tank, which means they give birth to LIVE fry (babies).  Yes, the female that died could have very well died while giving birth or shortly thereafter, it is quite common.  Doesn't happen ALL the time, but yes, it does happen more often then us breeders like to see.

The egg sacs on the wall sound more like snail eggs.  Do you have snails??  If so, that's probably what they are...they are gooey and attach themselves to the side of the tank right at about the water line.  You can just wipe these off with a paper towel (even if you don't have snails).  

The males of these fish have something on the bottom underneath fin that looks like a straightpin, whereas females have more of a "v" shaped fin underneath.  The males "gonopodium" inserts inside the female and fertilizes the eggs inside her.  Now, with 1 fertilization, a female can have up to 7 batches of fry WITHOUT being fertilized again.  SO, be prepared for LOTS AND LOTS of fry!!  After you have fun having some in a breeding net, you MAY just want to let the females have the fry in the main tank because you will VERY QUICKLY become overrun with fry and no where to put them.  I bred them on purpose and had 5 fish tanks going - 2 10gal for small fry, 1 20gal for medium fry, 1 20gal for larger fry and my main 75gal tank and a "sick" tank or "hospital tank" (for any sick fish).

These fish can have anywhere from 5 to 80 fry at a time (the mollies have larger batches because they are larger fish).  So like I said, that is a LOT of fish.  If you let them have them in the tank, nature takes its course and they get eaten and only the fast and strong survive...it's natural to happen and that's how it happens in the wild, it's not "mean".  It's "fish life".

Sometimes they lay low right before they release the fry.  HOWEVER, if your fish is very fat and looks like a porcupine, then there is probably an illness called dropsy.  However, at this point, if it's the only one doing this, she's probablby going in to labor.

If you do not use "aquarium salt", PLEASE purchase some and use it in your tank according to the directions.  Mollies (and all livebearers to a point) need this salt in order to thrive, as mollies are actually a brackish water fish.  The other livebearers can deal with the salt in the tank. (NOT marine salt, just regular aquarium salt). The directions are on the box.

There is so so so much information about livebearers available online. Please take some time to research some and learn about these awesome fish!!

Good luck!