Fish tail

Question
I have a male betta crowntail and 2 female bettas in a 6 gallon tank.  Is this appropriate and how often should it be cleaned?  Also, the male Clyde, his back fins are stiffer, not flowing like when we first got him.  Is this a sign of fin rot?  I don't see any other signs.

Answer
Hi Cara,
  That is a little bit tight... it would be better if they were in a larger tank.   The general rule for fish tanks is that you should change 25% of the water once a week, every week.  This is far better than changing all of the water at once or some such thing.  As for the fins being stiffer, I don't see that that would indicate fin rot.  It could easily indicate that he is holding his fins stiffer because there are two females in the tank...

-- Ron
  rcoleman@cichlidresearch.com
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