Have successfully breed and raised mollies, guppies, swords and platties for the last 3 years. About 6 months ago started noticing my females will have a big belly, but in fact there is no eggs let alone babies in them. Not sure if I over medicated them? Made them sterile? I had started using a Pur water filter about that same time frame as I discovered have metal flakes in my well water. Could this have caused something? Any help would be greatly appreciated.