betta keeps leaning, unable to stay upright

Question
Hello, Elizabeth,
I hope you can help me. My betta is unable to stay
in his normal upright position. I checked online and
am aware of SBD. However, in the articles they spoke
of bettas unable to stay at the bottom and kept floating to
the top. That is not the case with him. He has to lean
against things to stay upright. His eyes are dull.
His mouth is half open sometimes. He still has an
appetite. This started when I had some out of town
guests staying with me, so I suspect they might have
overfed him. He has a med. sized filtered tank which
I clean with spring water once a month. I turn the tank
off at night, so it doesn't keep my son awake.

Thanks,
Chris

Answer
Unfortunately, you need to clean you tank more then once a month.  Even with a filter you need to do a 10-25% water change each week.  The symptoms you describe don't fit any particular illness.  Get your LFS to test your water for you.  If it is not a problem with ammonia, nitrites or nitrates, then I am inclined to think it is a parasite problem.  Try a general parasite medication.  Just in case he was overfed, cut back on the amount of food.  Betta's are often overfed.  A healthy Betta only needs a small amount a day.  I prefer to feed pellet food or insects in gel.  My Betta only gets 4 small pellets a day.