White patch on cory

[eternal_irony]

When i was feeding this evening I noticed that one of my sterbai cories had a badly ripped tail and on closer inspection he has a white patch just behind his dorsal fin.

I've not had much experience with fish illness/injury but my fist panicked thought was that it looks like columnaris but it looks more like his skin has been ripped or is peeling slightly.

I've decided to ask the experts and see if anyone can shed any light on what it could be and how I should go about treating it.

Any help would be very gratefully appreciated.

 

[eternal_irony]

Forgot to add
Tank parameters
Temp 25oC
PH 6.8
Ammonia 0ppm
Nitrite 0ppm
Nitrate 5ppm

 

[V227]

IMO, looks like an abrasion, with a fungus attached to the damaged tissue. Nothing to be worried about. Clean water and good nutrition should heal it up.

 

[eternal_irony]

Thanks, it's already looking better