Hi. I have a crown-tail betta named Rooster. We've had him for about 6 months now and up until a few weeks ago he was in a one gallon acrylic aquarium. A few weeks ago we moved him to a 5 gallon glass aquarium which he loves. About a week after he got moved into the new aquarium, I noticed that most of his tail was missing (this happened in the span of a day or so). I panicked, but then read online that sometimes they bite their own tails. I noticed, then, that he was staring at his reflection, but I have not ever seen him fight his reflection. I tried to put up a background, but he went crazy and couldn't calm down. So, now I have up dark construction paper on 3 sides of the aquarium to help with the reflection. However, he can still see his reflection when I have the aquarium light on and all he will do is sit in the corner and stare at himself. Then I notice that the little bit that had grown back on his tail is gone.
Now I have to leave the light off so that he doesn't see his reflection. Is there something else I can do?? His tail was so long and beautiful, and now it's so short! I've been changing his water frequently and treating it with Stress Coat to prevent infection, but I don't know how to keep him from fighting his reflection. I would really like to have the light on for him during the day, but as soon as I turn it on, he races back to that corner to stare. Help me please!! Any ideas on what else I can try??