I moved our betta to his own 5 gallon tank after the current in the 14 gallon tank seemed too strong, or he wasn't handling the cycling of the larger tank well, or just because he stopped acting like himself. I can control the water temperature better and now it's a shade under 80.
I do full water changes once per week and monitor the ammonia. His fins did seem to be getting a little ragged in the larger tank, but it was hard to tell.
Tonight, however, I noticed that it looks like his top fin has nearly disappeared. You'll notice it looks like someone took a scissors to it and snipped it on a straight line. There's no fuzz on that line, but I'm not sure what to do.
This makes me sick. Help?