molly fry suddenly dying

[MiamiCuse]

I had 16 albino sailfin molly babies born about three weeks ago. So far all have survived and I had them inside a small breeder basket with the main tank. They have been feeding and thriving and I could see them getting bigger.

Then since Thursday I have been losing two a day. So far I have lost seven, I have not done anything different, water test out ok no ammonia no nitrite a bit of nitrate which I take care of with water changes periodically.

I noticed on some of them they had a few white spots on them, very small, almost like the size of a needle point, mostly on the fin and tail areas, not sure if it's related.

Any thoughts on what I can do to reduce the loss?

Thanks!

[AquaBANG]

they could be itch.
do you have a spare tank that you can quarantine them.
I had the same on my guppy fry about 2 months ago.
I raised the temp to 82 deg and treated with salt.
I lost a few, but quite a lot survived.