I have had my male half-moon betta for about about 1 1/2 months and his tail is really ragged. He lives in a filtered 10 gallon tank that stays about 82-83 degrees. His tank was cycled but I get a new filter so it's not any more. (I have been struggling to keep the ammonia down, but I just added ammo chips today so that should help. Even when his cage was cycled, my betta's tail began to slowly get more and more shredded.. He had sharp plants in his cage which I removed, but he just kept getting more shreds. It looked like someone took some scissors and made little snips all down his tail.
I thought he had fin rot, I treated him with maracyn 2, but he didn't recover. The night after I finished it, I woke up to find that the number of shreds on his tail had dramatically increased. I was really worried and thought he had extremely severe fin rot. I am currently treating him with triple sulfa, which I have been using for 3 days. While his tail doesn't look worse, it's not noticeably better either. Here are some actual pics of him. Sorry that are kind of blurry.
Here are some better pics I found on the internet that look almost exactly like him.
What does this look like, fin rot or tail biting?