We have had our betta Dirk for about a year. About three weeks ago he started swimming oddly. A few symptoms:
1. His body tilts to the side (about 45 degrees) so he is not completely vertical.
2. He seems to thrash a bit, like he is frantic or at least working harder.
3. His tail fin seems a little curled up; it is never straight behind him.
4. Sometimes when he is just hanging out, he floats on his side (scary).
5. He also seems to be hanging out in the corners of his tank a lot and seems pretty lethargic until we come up to the tank to talk to him. Then he proceeds to swim as described in the first 4 items...
He still gets excited when we get near and will usually eat and follow our hands across the tank to get food. His scale surface seems a little dull/grayish but no noticeable spots or fin rot.
We thought it might be swim bladder disorder brought on by constipation so we stopped feeding him a few days, but that didn't seem to work (and he pooped during that time). We fed him a blanched pea which has worked in the past when he seems bloated but no luck. He also had similar symptoms six months ago and we used Maracyn Two which fixed it. We tried that again but it didn't make Dirk better this time.
We cycled the tank a while back. The water is pretty cloudy although we don't see any large particles floating around. It has been cloudy for a long time though (more than three months).
2.5 gallons of water (the tank is 5 gallons total). Aquarium gravel at the bottom.
< .25 ppm ammonia
7.1 pH (we adjusted it from about 7.3 three days ago and it looked like he got a little better but then regressed again).
Tank has no filter
We don't change the water very often; we add about 3/4 gallon a week but don't usually take anything out since the water just evaporates. Online there is a lot of conflicting information online about how frequently to change water so we're not really sure how to handle it (but he has been fine until recently with our strategy). That could be a clue to the problem. We add a basic conditioner for ammonia, chloramine, etc. when we add the water.
We really have no idea what else it could be. We have read a lot but can't find anything specific to our situation. Any advice or ideas of what our next step should be?? Any help is much appreciated! We want our little guy to get better!