Lesion on one spot foxface

[Seadoc]

Hi all,
Need help with the appropriate approach to what I am seeing in my foxface.
Today I discovered a somewhat round lesion next to his right side spot. He seems to be behaving normally. Swims without any problems and eats like a pig. Any ideas what this could be?
Other fish are behaving normally as well.

Parameters:
Sal: 1.025
Nitrates: 2.5
Phosphates: 0.11 (going down)
Alk: 9.11
Ca: 450
Mg: 1311

Any advice will be appreciated.

 

[vetteguy53081]

Appears to be bacterial and treatment is needed.
May be associated with poor water quality and inadequate diet or both.
Check Ammonia-nitrate-ph- salinity.
What foods are you feeding?