Sick s silver dollar?

[Ac30fan]

Just performed routine water change & noticed orange patch just behind the gill of silver dollar fish - see photo

I'm a rotten photographer, and this is the best pic I could capture.

Water conditions are fine. I typically do a partial wc weekly



Any input is appreciated.

 

[thomasina]

Fish Treatment


Take a gander at this site and maybe you can see if it describes what your SD has.