my blue betta (prince) lives in a 3 gallon tank, I do 20%-50% water changes every 3 days. The tank has an airstone filter. Ive had him for 2 weeks. My red guy (elmo) lives in a small, 1.5 gallon tank, with a filter, and a heater. I do the water changes the same as prince. They both have a bulb plant in em, with some fake plants and both have a bridge. I try and feed them only once a day, 2-3 pellets which I cut in half. As far as water goes, I boil it, and still add a water conditioner.
I just noticed the white fuzzy looking stuff today. My elmo right now is not moving much, underneath his bridge. he might be sleeping Im not sure.