Hello, I wonder if anyone can help me work out how to help my sick Plecostomus catfish. A couple of days ago he started floating upside down on the surface of the tank, and now is spending his whole time suckered to the back of the tank with the middle part of his body sticking out above the water surface - also for a short period yesterday he was apparently wedged into the hollow log at the bottom of the tank. From what I've read online it seems likely he has a swim bladder problem, but I have no idea how to treat this. Commonly this seems to involve a bloated stomach, but if anything my fish's stomach looks sunken. He also has a few other symptoms - a sore on his side (though this looks better today, and may just be a heater burn), some erosion to his fins and he doesn't seem to be eating at all. I have tried putting cucumber in the tank which I have seen suggested by some people for swim bladder problems, but he hasn't touched it. I also think he looks a little paler than usual but it could be my imagination! He seems lethargic and unresponsive to my gentle attempts to touch his tail and encourage him to move around a bit. I have had my water tested, which is fine in all regards - at the suggestion of a local tropical fish shop I have done a small water change and instead of using standard dechlorinator as usual I have used API 'Stress Zyme' and 'Stress Coat+', and am putting in an antibacterial medicine called 'Melafix' (also by API) daily. If anyone has any suggestions of how I can help my fish I would be extremely grateful. As mentioned he is 18 years old, and is the only fish in the tank so cross contamination/stress etc. are unlikely to be causes of any infection or illness. Thanks very much for your time.