We recently started a 10 gallon tank for my daughter's birthday. Unfortunately we overstocked and got some diseased fish. As you might imagine a lethal combination. We lost everything but a ghost shrimp and an algea eater. We decided to start over from scratch the right way. We dumped the old water, got new gravel and plants, let it run for two days empty and then started with 2 platies and 3 neon tetras along withour two surviviors. I have kept close track of the levels and watched for disease. This morning one of the neons was dead. Both of my platies are very fat, but one of them hides most of the day except when it is eating it will swim around for a few minutes and then it goes back into hiding. It has no spots or red marks. I am not sure if I have a pregnant fish or what? Please help!