I answered a similar question like this a couple of weeks ago. When my Tiger Oscar had HTH, I didn't use any meds whatsoever. I placed her in a hospital tank, did large water changes and fed her a variety of different foods. Within a week, the holes were almost closed and after 1 week and a few days, they were closed completely. I put her back into the 225 and she's been fine ever since. What's your water condition? Are you feeding your Oscar the same thing day in and day out?