My betta is not very active

Question
Hi, I'm not sure if you are very familiar with Betts because it said you knew cichlid fish, but you were the only one I was able to ask so here we go.

I have a male Betts that lived in a 10 gallon tank for a few months, he recovered from popeye and has been fine since.

Anyway.  He got moved to a 5 gallon tank with 3 other females, one that I believe is not ready to breed because of the horizontal lines on her body, and the other 2 are of the age to from what I'm seeing.  Well, when the Betts was introduced to the other females I enjoyed seeing him flare up trying to impress the females.  Now I'm not sure if he built a bubble nest at all because there were bubbles at the top of the tank.  But because of the filtration system IF he built one the bubbles were popped.  The females were introduced about 24 hours ago and it seems that the male is not very active anymore.  He sits at the top or the bottom and does not swim around as much.  He also seems reluctant to eat at times.  I have tested every day, and my levels have been quite stable.  My nitrates are low, my nitrites are at a good level, the water is very soft, my alkalinity is moderate, (a little below ideal) and the pH is neutral.  

Any ideas why he all of a sudden became so inactive?

(also. he was originally in the tank with 4 females, but one contracted popeye.  I bought her from walmart. surprise surprise. so I removed her from  the tank)

Answer
Hi Dan,
  A 5 gallon tank is not a lot of space for a male and three females.  Also, you will need to do something about the filter because the male needs pretty still water to build a good bubble nest.   

-- Ron
  rcoleman@cichlidresearch.com
  Cichlid Research Home Page <http://cichlidresearch.com>