Hello, everyone. I would like to get some advice on a red tailed shark that is showing signs of sickness. Its fins are clamped and it just sits on the bottom of the tank or in it's cave not swimming much at all. It is much more active at night though. I have noticed that it will stay in the current from the filter or by the air stone. Has no white spots or cottony growth on it, but some of its scales look kind of gray and my tiger barbs bash into to it from time to time. It used to be the ruler of the tank and would chase the other fish around, but doesn't do that any more. Water temp and levels are all okay and no other sick fish. Any ideas what's wrong with it? How do I treat it? Any ideas you all have would be much appreciated. thanks.