Corydora Alive Laying On Her Side With White/red Patch

[missdora]

Hi All
 
I looked into my tank this morning and one of my corydoras was laying on her side...breathing normally (photo attached) .
 
I don't have a quarantine tank so I put some tank water in a bowl and put her in there. as she turned I noticed a large white/ red patch on her side.
 
We have had all the fish for nearly a year, no new ones, water change 3 days ago and water tests are normal. 
 
Is there anything I can do for her, or just accept its the end for this one? does anyone know what it is? I tried googling but nothing came up
 
Thanks

 

[fluttermoth]

What are the actual numbers from your tests, OP?
 
How big is the tank and what fish are in it (numbers and species)?
 
She looks pretty far gone and I wouldn't expect her to pull through, I'm afraid. There's not enough info or specific symptoms for me to advance any kind of diagnosis.