cichlid with black head

Question
Hi Ron, no golfish questions here...lol.   I have a tank full of cichlids.  Recently I have noticed one of my yellow labs head is turning black on just one side...it almost looks rotten or more like it was rubbed with charcoal.  It's behaviour seems normal and no other fish in the tank are showing it...any ideas as to what it could be or could it just be its marking?  I can email you a pic if you'd like.

Thank you,

Aaron

Answer
Hi Aaron,
  If it is just one side, e.g., the left side of the head, then this usually indicated nerve damage.  I have seen this on various other cichlids before, sometimes it is the head, sometimes the back quadrant of the body, but the telltale symptom is that it is only on one side.   It doesn't seem to affect them much but it is very interesting.

-- Ron
  rcoleman@cichlidresearch.com
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