Platy Not Able To Eat?

[coyemuse]

So I moved one of my variatus platys to my 10g fry tank cause she use
to be round and healty and now her round tummy is like flat-ish. I fed
her and the fry this morning and watched as she tried over and over to
eat the flake food and couldnt. Whats happening and how do I help
her? I dont know how long she hasnt been able to consume the flake
food. Should I try fry food since its small and easily consumed?
 
Also, Just looked at her for a few more minutes and noticed a small
injury to her side just behind her gills, could this be the cause? How do
I help her heal?

 

[Timberbatch]

Could you maybe take a pic of the injury as best as you can? I know how hard it is to photo fish but it would help with diagnosis immensely Also how are the parameters of your tank?