Platy fry problem

[MommyMelzy]

My female platy gave birth on January 23rd. I have 8 fry in the breeder tank. 4 of them swim around normally but the other 4 just lie on the bottom. Their eyes move and their fins are moving, but they don't swim normally. When I put food in the tank, they swim up to get it but it's very strange the way they swim...almost like a corkscrew. They go up and then just come right back down. Anyone know what's wrong with them? They are 8 days old now.

[Laeris]

I'm so sorry the babies aren't all doing wonderfully I have no idea what's going on with those little guys. It could be they're underdeveloped, or there might be something more serious. Not every fry of every batch is going to be viable. In the wild, they simply get eaten. In aquariums, it's up to the individual to decide at what point deficiencies warrant euthanization.