black convicts

Question
two of my fish have been floating around the tank nose down. Other than that they act fine. What can cause this?

Answer
Hi Doug,
 Hmm... that doesn't sound good.  They could have been attacked by other fish.  Alternatively, it could be a sign that your water is not in good shape.  Are you doing regular weekly water changes?  You should be changing 25% of the water once a week, every week, to keep your fish happy and healthy.

-- Ron C.
  rcoleman@cichlidresearch.com
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