Today is the 3. day that my platy rests on the bottom of the tank. She had fry 3 times in the past 8 weeks, maybe that just wore her out. But I also read that it could be constipation. My book recommends magnesium sulfate. How does that affect the other fish since I don't have an extra tank to separate her (the babies are in my extra tank). Would that really help? Is there anything else that you recommend? I already did a mayor water change (90 %), just in case it would be the water (even though the water test didn't show anythig bad), but that didn't help.