I have to add some comments to this thread. Potassium Permanganate can be a very useful chemical when used correctly for the right things. It can also easily kill your fish. You need to be mindful of many factors like Organic loads, water conditioning chemicals etc all can interact with PP. Dosage and duration are important.
I've used it many times and many others do as well. I have saved fish and I killed fish with it, and anyone that tells you they haven't killed fish by accident with it probably blocked the memory because its not something we like to remember, or they used so little it probably couldn't cure anything.
But what is Potassium Permanganate.? Its not a medicine. Its a chemical oxidizer. It literally destroys organics and other things.. What are Organics? Bacteria, virus, protozoans, worms,flukes etc are all organic which is great right? Sure, but the fishes Gills are also. They are the site of most gas exchange and much other uptake into the fish. They are sensitive to irritants which is why they are irritated by flukes and parasites feeding on them .. They are also irritated by chemical burns from oxidizers. Theres also alot of work that shows that these oxidizers like PP can cause long term damage... we've seen many adult discus here with thickened protruding gills..no proof but I bet its from too much PP as a frys and juveniles. Somewhere on this forum we had a discussion once and there were pictures of gill filaments and deformities in them from chemical oxidizers called Clubbed Lamellae. I can't find that one now, but see this...
http://link.springer.com/article/10....639-014-0625-1
translated into simple english.. PP damages gills... so use it wisely and I wouldn't recommend it on fry, Their gills are developing rapidly and any damage is sure to have long term consequences.Also, the histological investigation showed a range of histopathological alternations in gills tissue including lamellar necrosis, hyperplasia, lamellar adhesion, haemorrhage, clubbing of gill lamellae. The severity of these alternations increased with increasing of the doses of the copper sulfate and potassium permanganate. In this regard, the highest histological damages were observed in 15 mg/l copper sulfate and 5 mg/l potassium permanganate respectively. Our results showed that low dosage of potassium permanganate has best effect on reducing of bacterial load of skin with lowest adverse effects on gill tissue.
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