Ailing Cichlid

Question
Hi Ron,
I have 5 African Cichlids and a red belly shark in a 30 gallon aquarium. I have had the aquarium and the same fish for about a year and a half. Recently I noticed that the scales on one of my cichlids, (orange in color), appeard to have turned white in areas on its side. Almost immediately, its tail began to deteriorate. It began to hang out at the top of the tank in the corner and would not eat. I bought some Melafix yesterday and treated the tank. The spots have now become pinkish, the tail seems to have ceased rotting and it appears to be eating some, but I am not 100% this is true or if it is wishful thinking.
Any suggestions?
I am also interested in knowing why their lower jaw, bottom mouth area appears to become black from time to time.
Thanks for your help!

Answer
Hi Theresa,
 The black jaw and the damaged scales are actually related to the same thing -- your fish are fighting.  They might not do it when you are around -- this is often the case -- but clearly the one fish is getting the *$$!!! kicked out of it.  The damaged scales and deteriorating tail are from biting by another fish and to avoid this, the fish is trying to hide but the best it can do is go to the top corner (a common reaction).  You need to either remove the fish to another tank or put in more "structure" in the tank, to create more hiding places.  Structure can be wood, rock, plants etc that break up the space.  This is the best long-term solution.
 The black jaw is from lip-locking which is what many African cichlids do when they start fighting.

-- Ron
  rcoleman@cichlidresearch.com
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