One of my Angels is not doing very well. I've had them for about 4 yrs. Last Sat. I noticed the it was missing one of it's side fins. Not sure if one of the other two bit it off or what happened to it. The little nub barely sticks out and having difficulty swimming.
So after the first day it sits on the bottom of tank then after the second day it's lying on the bottom.
It looks dead but every time I tap light by him it comes to life and swims up to the top, which is very difficult for him to stay afloat, then comes back to rest on the bottom lying flat. Tonight I got it up while I was feeding and it ate one piece then back down but not lying flat now.
Am I slowly watching him suffer?
Anything I can do?
The other two Angels are perfectly fine. Perfect fins.
1/4 water change once a month
Ammonia, Nitrite 0