about 6-7 weeks ago we had mollie fry in our tank, 11 in total ( well what we found in the morning anyway!) but two died in a couple of days,so left us with 9, so we went & bought a hatchery & fished them out & popped them in, they were happy enough in the tank floating about with all the other fish, 2 of them were looking a bit small so we went & bought another hatchery and put them in, so thats 1 hatchery with 7 in & 1 with 2 in, we woke up this morning and every one of the 7 are dead on the bottom of the hatchery!! the other 2 are fine ( up to now) all the other fish in the tank are thriving with no probs at all, how can this happen, all the 7 fry in the hatchery all die at once??? whats gannin on???