Betta's Fins Disappearing?

[TotallyTropical]

I recently moved my lovely little betta to my 10 gallon, since no one was going to be in it anymore. He seemed quite happy with the larger switch and was relatively fine for a while. Recently though, I've noticed that his tail was ripped to shreds, all the way down to his body. I checked to see if it was fin rot, but it didn't look like it at all. Now there are two gashes on the side of his body, and something fungus like seems to be covering part of his right eye. The tank was completely cleaned out before he moved in, he has absolutely no tank mates, and there are no sharp decorations in the tank. I tried treating him with some Melafix for a week, but his condition just seems to be getting worse. I did a water change today and replaced the filter, and I'm just hoping for the best now. Other than that, he still seems fairly energetic and eats normally, but he doesn't like to flare for me anymore. Any ideas on what happened?

 

[wet44]

I don't have any idea what the problem is but I would suggest moving this post to the emergency section. Hope your betta's condition gets better.

 

[TotallyTropical]

Thanks, but I unfortunately waited too long.
The poor guy went completely downhill after the water change. He bloated up, sank to the bottom, started gasping, and looked to be in a lot of pain, so I had to put him down.

 

[NickAu]

Sorry to hear that.

 

[RobRocksFishTank]

For future reference:
 
it could have been the tank was cycling. You probably would have been better off just doing a good sized water change instead of totally cleaning it.
 
Instead of treating right away. The first thing to check is water conditions. A simple water change may have been enough to save him.