Dead fish, no known reason

[Allix]

Cant platies/guppies/and mollies interbreed?

 

[Bloo]

to my knowledge Platies & Swords yes. Mollies no.
Guppies with that lot would be a "no" too. Guppies and Endlers, yes.
Someone please correct me if I'm wrong.

 

[daudy_dojo]

liquid test kits work so much better than strips i can use a strip and get a .25 ammonia reading but when i use the liquid (since i know its an astablished tank) the reading for ammonia will be 0

 

[Allix]

I had a close look at the tank this morning, and it looks like there is white stuff growing on the glass

 

[Tokis-Phoenix]

to my knowledge Platies & Swords yes. Mollies no.
Guppies with that lot would be a "no" too. Guppies and Endlers, yes.
Someone please correct me if I'm wrong.

Mollys and guppys can also apparently crossbred, but this is very rare.

Even if you don't have a male orange molly to mate with her, it is most likely she mated with one in the lfs or at the breeders and mollys like other livebearers can store sperm in them for up to 7 pregnancys- so she may have some fry that belong to another dad and also your own if you have a male in the tank.
Either way though what type of livebearer you have doesn't matter as they should all be raised and can be raised in the same way and their requirements are the same, mollys and swordtails just take longer with the whole reproduction and fry growing process in comparison to platys and guppys thats all.

What temp is your tank set at and how much are you feeding the fry on average and what?