So, I have come to the conclusion that my fish is tailbiting. One day, a large portion of his tail was just gone and there is no sign of fin rot. I thought he may have been stressed from having his light on too much and seeing his reflection, so I started leaving his light off, which worked; his tail started growing back. I was recently gone for a week and I came back to find his tail bitten again :-/. Is there anything else I should be doing to stop him from tailbiting? I am keeping a close eye on his tail and making sure there are no signs of fin rot and I add aq. salt with each water change. This is my first experience with tailbiting, so I'm wondering how others have dealt with the issue.