I have had my male betta for over a month now and I feel like he just doesn't behave normally. However, I have been unable to identify an exact illness. He always eats very well, has no fin rot, or visible abnormalities like parasites or fungus and yet he is not very active. He tends to just lay at the top or bottom of the tank, slowly tilts over and then moves a bit to correct himself. Of course, you would think swim bladder issue, but he has no trouble swimming and is actually very agile during feeding.
He is housed on his own in a 2 gallon aquarium with a low flow filter and heater that maintains the temperature at 79F.
I do partial water changes daily and whole water changes weekly.
He is fed twice daily varying between flakes, pellets, and frozen bloodworm.
I check ammonia, nitrate, and pH every few days and the levels are always within the normal ranges.
Does anyone have any suggestions?