Hello I have a problem and I have to medicate big tank before it gets worse. Here is some info about my tank to let everybody know this is not a water quality issue... The tank is cycled---Ammonia-0,nitrite 0,nitrate is at 10. Temp is 80 and ph is at 7.6. I do water changes every 5 to 7 days of 25% to 40% with gravel vacuuming as well with the water changes. This is going to be a long post and I apologize in advance. All my problems started in August of 2012 when I purchased some cardinals that I did not quarantine before putting them in the big tank that was a huge mistake. Anyway they all looked ok but then they developed Ick and everything has went down hill from there. I wanted to try and save them without hurting my filter bed or my otocinclus or my corydora's so I decided to use heat as a way to kill the Ick. This is what I did I turned the heat up to 86 and left it there for 2 weeks and every 2 to 3 days I think it was I vacuumed out a 3rd of the tank every time I done a water change. Anyway I thought things where ok the heat treatment did get rid of the Ick but later the fish started getting sick I have lost Platy's and Corydora's to not eating laying on bottom,breathing hard, some at surface some not,pale,weak,clamped fins and some flashing. I thought at first it was just stress from having the Ick and going through the heat treatment but that just isn't the case. I have lost some Cardinals too with some different symptoms like the bubble on eye and white stuff on fins as well as some bloating or something which I think all this is tied in with the flukes. You know all the bacterial and fungus secondary infections. Almost everybody in the tank is effected in some way. I had a cardinal that got a bubble on his eye and some kind of white stuff on his fins. I had a corydora die from fin rot and some die with just breathing hard and pale laying on bottom and to weak to swim to the top of the tank. All the fish that have gotten sick I have took them out and tried to save them in a quarantine container hanging on the tank but they have all died. To make things worse I had some fish that where fighting which couldn't help on the stress they where already under but I have since removed those fish. Ok I'm thinking it is gill flukes and skin flukes and I'm thinking about using Quick Cure but I'm concerned about my corydora's and my Otocinclus. Has anybody use this medicine half strength with this fish? At this point I'm not concerned about the filter bed but my fish. If I don't do something I'm going to lose more fish. The only fish in the tank that doesn't seemed effected is the Harlequin tetras and the Honey Gourami. I have also tried the Prazi-pro and it didn't work, so I need to find something else that will kill gill flukes(Dactylogyrus) and skin flukes(gyrodactyylus). Please if anybody had used Quick Cure on Otocinclus and Corydora's half strength. OR if anybody might know something else with formalin or malachite green in that might work please share with me. I'm really thinking about getting out of the fish aquariums for a while after all these fish are gone because I have had so many problems. I'm about over it all! SO please help if you can I would really appreciate it very much! Thanks my friends!