Sick Parrot cichlid

Question
I bought an orange coloured parrot cichlid around 6 months ago.  In the last 3 months, its condition appears to have deteriorated and a large part of its body and face have black marks on it.  I have been changing 30% of the water once weekly, and also used anti internal bacteria treatment and as a desperate measure anti white spot treatment (although not at the same time).  The fish appears to have developed catarracts on both eyes, and I am not sure it is seeing as it does not appear to be feeding any more.  It is swimming normally. The fish tank size is 48"x24"x12", and I have 2 large internal filters in it. It is a well established tank and none of the other fish (there are around 15 samll to medium sized fish in total) are showing any symptoms.  Thank you in anticipation.

Answer
Hi Caroline,
  Do not put in medicines that are not directly for the problem at hand, they can make the problem worse.  So, do not put in white spot medicine unless your fish has white spot.  

  The most likely reason for the symptoms you describe are that another fish in the tank is attacking that fish.

-- Ron
  rcoleman@cichlidresearch.com
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