Oscar with pitting/missing scales on head

Question
Ron,

I have a 55 gal tank with a TetraTec PF300 filter with an inset heater. The only fish in it is a 13 inch red tiger Oscar. He has a good appetite and is active (eats thawed frozen krill), but there are pits on his head and face that look like scales have been pulled out. I checked the water with a kit for pH and nitrates and nitrites. All the results were within range, and his water temp holds at 79-80. I did a "my bad" and fed him feeder goldfish some months back. Do you have any idea was caused this pitting and how i might correct it? I feel really badly about my bud looking bad, even if he does bite me when he can.

Answer
Hi Marsha,
 Are you doing regular water changes?   You need to be changing 25% of the water in his tank once a week, every week to prevent that pitting.  

 Also, don't ever feed him goldfish again.

-- Ron
  rcoleman@cichlidresearch.com
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