I came home to find that my betta fish's tail (the hind tail) was missing a piece, and the only thing in his tank that could have caused that was the filter. I took the filter out, but now I'm worried his tank might get too dirty and cause him to get diseases. My questions are: 1) should I medicate him to try and regrow his tail? I put him on Melafix before and it made him sluggish, I'm scared to medicate him again. 2) should I put the filter back in, do frequent water changes, or just leave the tank as is with my occasional water changes?