I had a 7" Royal Panaque(L191) in with a 7" Rhino Pleco and a 6" Marbled Sailfin Pleco and various other fish. The rhino developed a spot of fungus and it then spread to the royal. In about two hours the fungus spread and consumed the royal completely. I use pimafix and melafix religiously to treat because I think they work the best of any meds I have ever used. The fungus is almost gone on the rhino but my royal died within hours of contracting the disease. I have never seen a disease spread so rapidly and kill a fish so quickly. The two plecos were the only ones effected. My rtc, pacus and other catfish were not harmed but there was no saving the royal. Any ideas on what this disease may have been and why my rhino hasn't completely gotten over it?? I have changed the water, cleaned the tank, and changed the filter cartridges twice this week but my water is still green and the rhino still affected.