Originally Posted by
discuspaul
It could be the early beginning of HITH, or simply a lesion caused by having run into or scraped itself on something.
Rather than starting with medication of any kind, for now I would suggest simply continuing large (at least 50% or more) daily wcs, if that's what you're routinely doing now, or raising your wc regimen to that level for a week or two to see what developments occur.
Lots of fresh water can improve water quality significantly, and help to remove, stop up, or heal many little health problems such as that discus is experiencing.