the babys on the way???

Question
hi Jamie,my name is monika and i have a problem. i have 8 fish in a 20 gallon tank, (by the way is 8 enough? or can i add some more) Anyways, i have a red velvet swordtail and i think she's pregnant. I started my aquarium about a month ago and got her about a month ago. Right after i fed her for the first time, she became chubby ever since. She eats normally, but wouldn't she have given labor by now? ( if a filter has anything to do with this, i have a 50 power.) any help would be appreciated. thanks.
*^Monika^*

Answer
Many livebearers like swordtails will hold their babies in until the feel the water conditions are acceptable. If you just started that tank a month ago, you are most likely going through the nitrogen cycle.  Fish poop, and this breaks down into ammonia, which is fatal to fish.  In time, a bacteria will colonize your filter and "eat" the ammonia.  During cycling, it is important to check your ammonia every morning and night and change 50% of the water whenever it gets above .25.  After the bacteria "eat" the ammonia, it gets turned into nitrite, which is also fatal to fish.  In time, another bacteria colonizes the filter and "eats" the nitrite.  Check the water every morning and evening and change 50% of the water every time it gets above .25.  The waste made after nitrite is eaten is called nitrate.  You remove this every time the water tests above 10. Usually 50% water changes weekly keeps this down.  I would guess that you are at the point where you have some ammonia and some nitrite.  Your fish are not happy with their water, and she is trying to protect her babies.  Stick with just the 8, because if you have female livebearers, you will soon have too many.  good luck