ISTA Methylene Blue SolutionA solution that is commonly used for White Spot disease, Cotton disease, Velvet disease, and other external bacterial infections. Methylene Blue is also used to help sterilize and disinfect aquariums which may have been infected and can be used for protecting unhatched eggs against fungus. Does not affect nitrifying bacteria and should not be used unnecessarily. Note: This solution contains strong blue pigment and will stain the aquarium's silicone