Melafix and pimafix are some of the best products I have used to heal my fish. My female jack dempsey got beaten to the point of laying completely on her side and not swimming away when I picked her up out of the water. She was terrible and all I did was douse her with melafix and offer her flakes and within two week she was healed. I haven't used Pimafix as much as melafix, but I use it to take out some fungal growths on some driftwood, and the growth were gone in a day. Honestly, the only thing that IMHO is better than mela/pima fix is the aquarium salt/stress coat combo. I belive your sharks are scaleless catfish and therefore connot tolerate too much aquarium salt, so I say go with mela/pimafix.When my light is on the one barb swims like it is killing him. So now I only have the 6 Barbs 2 Gouarmis 1 black red tail shark and my pleco I will remove the Barb and watch him to see what happens. But in the mean time do you know of anything to treat my tank with? Have you heard anything good about Melafix and Pima fix. They both say they are safe for Scaleless but I am nervous about using anything anymore. I have never had issues with my tank before and I have had this set up for 7 years and I had a 55 before for many years and never a problem.