Methylene Blue is a cationic dye, used for the treatment of external fungal and bacterial infection, slimy skin diseases and white spot in both freshwater and saltwater fish. In aquaculture due to its anti-fungal and anti-parasitic characteristics it has commonly been used to treat fish eggs to ensure they are not lost to fungal overgrowth.
Methylene Blue is an aquarium-safe disinfectant and can also be used for the treatment of ammonia and nitrite poisoning.
A 25% water change before commencing treatment is beneficial, also please remove active carbon from the aquarium. Change up to 50% of the water on the 3rd day of the treatment.