We supply pure 1% solution Methylene blue (food grade) with carbon/carbon and it possesses bactericidal and fungicidal properties for the treatment of external bacterial and fungal infections in fish, as well as some skin parasites – such as ichthyophthyrus. Applied with Aeromonosis, Branchomycosis, Gyrodactylosis, Ichthyophthyriosis, Kostioze, Plistoforosis, Saprolegniosis, Hilodonellosis, Tetrahymenosis, Trikhodiniosis, works partially on ectoparasites. The drug is used in the form of 2 ml 1% solution per 10 l of water, the treatment period is up to 1 month. At the end of the treatment, activated carbon filters are used to remove the blue from the aquarium water. One bottle of methylene blue contains 100ml