Today, I noticed that Sky had disappeared. I looked around, curious, and finally saw his head poking out from under the filter. I unplugged the filter, and he swam away from it quickly. However, one of his fins was pretty badly torn. Here's a picture: I'm planning to clean the tank tomorrow when I have more time (I didn't scrub the algae or vacuum gravel last week) and the reason I have a divider in there is to try and control my pond snail population-- remember to quarantine your plants!!!-- by restricting them to that part of the tank. Granted, it doesn't seem to be helping. Anyhow, I was wondering on how to go about preventing infection in his poor tail? Again, I'll clean the tank up tomorrow and maybe take a better picture. Should I change water more? Get some medication? I have aquarium salt; should I use that? Should I feed him something special? Thanks!