Hey my platy recently just gave birth to like 15 fry and they basically all died over the span of a week, but she still looks a bit pregnant (another platy I have looks very pregnant) and they have both been pooping this white poo that seems to have the appearance of white pebbles in a sack all joined together. I feed them normal fish flakes and none of the other fish are experiencing the same thing. Do you know what it is?? Is it aborted/miscarried babies?? Or parasites?? I have put a photo