This post is aimed at new betta owners who may have experiened a similar issue. I'm a new betta owner. My guy is named Draugur. Since aquiring Draugur I have looked to this forum for advice, and have found it quite helpful and informative. In spite of the abundance of good information posted here I continued to have concerns about 'Gur (no criticism intended).
In the mornings he would be swimming happily around the tank and enjoy his breakfast, but when I came home in the evening he would have trouble swimming to the bottom of his tank, and when he did manage to struggle to the bottom he would bob back to the surface like a cork when he stopped swimming. He did not have any other signs of distress, but would usually appear less active. Having followed the advice on this forum, and other sources. I was pretty sure that I was providing him with a good tank enviornment.
He's in a three gallon tank with a Tetra Whisper 3i filter and a Tetra non-adjustable micro-tank heater. (I know, I should get an adjustable heater, but it works for now' the temps stay between 80 and 83.) I check the water chemistry every couple of days with an API liquid test kit, and change the water 98% about every week. So far the ammonia has always been 0 or at least <0.25ppm, nitrate levels 0, and nitrate levels 0 with pH levels always close to 7. The tank has a small clump of live plants, and mopani wood which continues to leach tannins into the water (in spite of a week of presoaking). I also add < 0.5tsp of aquarium salt per gallon to the tank at every water change. I feed one small Aqueon BettaFood pellet twice a day, with the occasional alternation with API Premium Pellets. I've tried freeze dried tubiflex worms, but he doesn't seem to like them. I hope to try some live food soon, but haven't managed it yet.
For about the past week I have been soaking his pellet for about five minutes before giving it to him. This seems to have helped no end in resolving 'Gur's presumed digestion issues. I did read, somewhere on this forum, that soaking dried food can be helpful for some bettas' digestion, but it seemed to be mentioned almost in passing. So I thought that I might highlight this as a potental problem/solution. I post this only in the hope that it may be helpful to someone new who's betta may be experiencing the same problem, and would welcome any comments or observations from more experienced betta keepers.