We need to follow the comment we are referring to.  So please, let's start over here. :)

With that in mind, on Wed Dec 6th, 2006 at 08:13:32 CST, you wrote:

"Ok the tank now has 3 male guppies, 1 pleco, 4 female guppies. The water was treated for Ick and fungus infections. Biological filtration is still good. Aquarium shop said ammonia, nitrites and nitrates are good. No signs of infections or parasites have appeared on any of the fish. There is plenty of aeration. Water is changed at rate of 3 gallons per week.

It was treated weeks ago by use of Jungle treatment tabs from Wal-Mart. The fish were kept in a small bowl and did fine until introduced together and allowed to breed. Then the females simply died in mid-birth.

Last night 1 female became the first to survive the night after giving birth. she has had 3 fry and is still gravid. Her activities still seem normal. With hope she'll be the first survivor. Went to purchase two new guppies but they were sick with ick and died while in quarentine.

Could the shrimp be the cause of death? The female I mentioned above was in a separate 2-gallon tank filled 1/3 with Java moss to give ample places to hide using spring water and some aquarium salt with a  bubble stone."

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Thank you for responding so quickly. The reason for my concern about the medicating was that some anti-Ick treatments either have an antibiotic or an "anti-infective agent and for disinfection". (My Jungle Ick Guard does anyway.) Those things can quickly kill off the beneficial bacteria in a tank. It can take weeks for them to re-grow and effectively process all of the ammonia and then nitrites being produced.

I'm glad that you checked ammonia levels with your shop after medicating. Has that been done since then? Levels of those fish waste chemicals can change dramatically, even from day to day. If a fish dies (and is biologically broken down behind a box filter or a rock) or if we overfeed (is there a flake on the gravel - there are probably more we don't see) or if we add a couple of female guppies to the three or four we had, the ammonia level, just through the normal metabolisms of the new fish (or left over food, decaying corpses...) can profoundly increase the level of ammonia. In turn the ammonia can ravage gills, get absorbed into the fish's blood and keep the hemoglobin from carrying as much oxygen, and even, by way of the bacterial processes used to break down the ammonia, soak up a lot of the free oxygen in the aquarium water.

That could suffocate even guppies. And it would start with those needing the most oxygen.

This is even more critical in a small 1 or 2-gallon contain, where a tiny bit more waste material can have a gigantic effect on the nitrogen cycle, even where the small tank had cycled over several weeks. And the smaller the aquarium, the wilder the chemical changes can be. That is why some here, despite the cost, have recommended that newbies start with a 20-gallon aquarium. 20s are just a whole lot more stable than a 1/2, 1 or even a 5-gallon container.

Disturbed some Guppyloggers a couple of years ago by mentioning that I was quarantining new 2" fish, one each to a wide-mouthed gallon jar, with no thought to cycling the things. (I'm dishonest with myself too often as it is without lying to myself on these.)

They were set on the glass top of a 15-gallon heated tank. The jars were pretty much the same temperature as the tank. Almost daily a 5-gallon bucket of water would be siphoned from that tank (and replaced of course with seasoned, heated water). The quarantine jars were dumped through a net (or somebody's fingers) and refilled with new water from that biologically active tank. The ride never seemed to stress the fish beyond the immediate event.

I never bothered to suggest that that should be done with females about to drop if kept in small containers (DOH!)

But Stan Shubel's method of placing a female in a gallon drum bowl about a week before she would drop, has been mentioned a couple of times here. Shubel likewise doesn't pretend that there is any cycle going on in the drum bowl. He places it in a warm place, feeds the female well and changes 100% of the water every day or two with water from an established aquarium (very possibly the tank the female came from.)

Kudos to you! That was wise checking the fish for disease at the shop. If they use the same net for the infected aquarium and other aquariums, I would be leery of buying much from that place. If I just had to have a fish from there, quarantine might start with a treatment for velvet. ;)

The fact that your females were dying, and sometimes in small containers and the fry that managed to get dropped and males which might be there are not dying, leads me to wonder if they were being hurt either by an ammonia build up in a small space and (or) a lack of oxygen.

I'm glad that your female made it yesterday. What was different about the situation last night?

I'm not trying to be hypercritical of you, because I've been in a similar situation and, as a grizzled veteran, should have known better!

In the second comment in this following thread:
http://www.guppylog.com/story/2006/11/5/195439/884
I mention how I very successfully killed all of the large female Endler's (P. wingei) in a 10-gallon tank with too much top cover. The males, fry and small females seemed to be doing fine. Presumably they needed less O2. But the nighttime use of a little oxygen by plants (for respiration and growth), the needs of a lot of little fish, the summertime warmth of the water (which holds corresponding less free oxygen) and the lack of oxygen exchange at the water's surface was a lethal combination for relatively large females. During the day, the duckweed produced a prodigious amount of oxygen and there were no problems.

Here's a somewhat similar case. We explored household poisons and UG filters:
http://www.guppylog.com/story/2004/9/17/22557/4394

So for you to consider: When new fish (and/or shrimp or snails or  a pleco which probably bulks more than everything else in the tank or anything else metabolizing food) were introduced to the tank, what happens to ammonia levels? Are very frequent changes made (with water from an established tank) in the small containers? Would a nitrogen cycle have been established in that small container?

Just as a tag on - maybe because this time of the year I must watch where small containers are placed - will the container be warm enough for the female guppy?  Are they out of a draft and on a warm enough surface? That probably is not likely to kill her, but temperatures fluctuating more than a degree or two daily are just another source of stress.