Failing betta

Question
Dear Ron,
Our betta, Bubbles, has always been a bottom dweller (he likes to hang out under the ceramic bridge in his tank) but until recently would always swim to the top just fine (esp when he saw us approach) and eat and gulp air vigorously. For the past month, he is eating less (we feed twice daily), more sluggish, and last night I noticed a whitish film on his underside (not on fins). That made me think he has some kind of infection but would love your opinion and advice. We have had him 9 mos, he's in a 1 gallow tank, we change water roughly weekly, with tap water and use  conditioner. We're placing a heater under the tank now as I am sure the water is too cold but let us know if there is anything else we should do.  

Thanks in advance,
Lisa

Answer
Hi Lisa,
 Adding heat is a good idea.  Air temperatures are often too cold for bettas at this time of year.   

 I am curious why you are placing a heater UNDER his tank, rather than putting an aquarium heater in his tank.  An aquarium heater is much more efficient and cheaper to run than other ways of heating a tank.

-- Ron
  rcoleman@cichlidresearch.com
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