1 Gallon Betta Tank: Cycling? Water changing? Help!?

you don't need to change all the water, just do 25% when changing and unless your over feeding you shouldn't have to clean everything off. Sometimes it's over kill on feeding and water changing can make them sick. A betta can live in a mud hole. They are strong fish in other words. The thing with these are you don't know the age of the fish and some times they're just old. If he's building his nest and all seems fine then he probably is great. Make sure he don't have ick, white spots on him. I always turn power off and clean my filter then I do a water change of 25% or up to 50 if your water is really dirty. The Bacteria base is in the gravel and should be ok.