HI guys, I have two pregnant platies and yesterday I saw one fry swimming about in the tank so I put it in the hatchery that I had bought when I first found out that the fish were pregnant. Because I have two pregnant fish I am not sure which one gave birth to that fry, as they both still have the gravid spot and are still quite big. I moved the baby platy to another tank, and put one of the pregnant fish into the hatchery because I was hoping that it would give birth over night. I woke up this morning and there were no fry in the hatchery. Both the female platies still look pregnant and because one of them must have given birth to that fry, that fish must be having some more very soon. This morning I let the platy that I put in the hatchery out because it was getting too stressed. How will I know when the fish is going to give birth and how can I tell which fish gave birth to that 1 fry. Also does the gravid spot disappear after all the fry have been given birth to?