What is wrong with my tank?

[dubleshortlatte]

I have a 5 gal tank that I used to house 4 baby mollies, MTS, and Java Fern. They were all healthy and doing well, but in the past week, I have lost all four of my babies. Three of them were born underdeveloped (They looked half-egg half-fish and i could see their hearts beating through a very clear abdomen), but they have survived nearly two months and been ok (born Christmas Eve). The fourth baby was born sometime in October and hadn't grown much, but only showed signs of sickness a day or two before dying. I did water tests, and my Nitrate is at 10ppm, my Nitrites at 0, 100 or so ppm total hardness, pH somewhere in the 7 range. All very healthy parameters....yet they all dropped dead. I don't know if it was becuase the babies were underdeveloped and unhealthy, or if there's something in my tank. I would like to use it to house a betta and some ghost shrimp, but i'm not sure if there's something that's deadly about my water! I do regular changes (once a week or two).

Thank you!

edit: My temperature is consistent at 74-78 degrees, and it is an eclipse tank with BIOwheel. I was feeding them normal flake food.

 

[Zagz]

Sorry about your loss. When you say he showed signs of sickness before dying what were the symptoms?
With a 5 gal tank water changes once a week are a must. It is harder to keep water stable with smaller tanks. Did you test for ammonia? Is there a heater in the tank? Even small fluctuations in temps can affect fry. The 3 you described as under developed may have not had much of a chance regardless of the fact that they survived for 2 months. It may have been one of those things that can't be explained. It may have been one of those things that was just meant to be.

 

[dubleshortlatte]

the symptoms were basically being sluggish...just resting at the bottom of the tank for extended periods of time. Not really being active at all, even for feeding time. I have a 5-in-1 test strip that does nitirite, nitrate, alkalinity, pH, and water hardness, so I did not test for ammonia. There is a heater, and the temperature was constant...no fluxuations. Thanks for your support!

 

[Zagz]

It may have been ammonia poisioning.It is possible to have an ammonia spike without any other parameters showing bad readings. It may also be as I say one of those things you have no control over. I would not worry too much but would get a test kit that tests for ammonia. The general consensus is that the strip tests are not always accurate so a test kit such as AP's master kit would be better IMO. Big Al's online sells them rather cheaply.