Beta Fish sick? Stressed?

Question
This was happening even when we had a filter going.
I read somewhere that when they act like this they could be stressed.
I haven't changed his water in a week or two because I thought it would be
too stressful. Plus it's not that dirty. It's also warm in our house so I don't
think he's cold.
Any other suggestions?
SHelley
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The text above is a follow-up to ...

-----Question-----
Our beta was doing fine. Then one day, just started jutting around the bowl
and now for the last few weeks - just sits at the bottom. Isn't really interested
in eating, very strange. We used some antibacterial stuff - as directed. Took
out the filter - it seemed to be freaking him out. Don't know what else to do.
Went down to feeding him only once every second day. He won't even puff up
at his reflection when we put the mirror up to him. He used to do that as well
as just before he'd eat. What are we doing wrong?

-----Answer-----
Hi Shelley,
 Have you been changing his water?  I change the water on my bettas once a
week.

 Also, is the water cooler in the bowl than it was in the past?  With winter, a
lot of people don't realize how cold their betta bowls get.  Cold will
dramatically reduce the activity level of a betta.  

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

Answer
Hi Shelley,
 You definitely need to keep doing the weekly water changes.  Consider changing only half the water; that will be less stressful and may help improve things alot.  Water doesn't have to look dirty to cause problems for a fish.

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