The NT Labs Methylene Blue is a must-have product for any aquarium enthusiast. This medicine can treat both bacterial, fungal, and external protozoan parasitic infections in your fish, fry, and eggs. It's perfect for both coldwater and tropical aquariums. Just apply 1 or 2 drops per gallon (about 10-20 drops for a 900L tank) every few days for up to 14 days to clear up these nasty issues. Safe for use on all common aquarium fish species. Don't let parasites and infections ruin your fish's health and your tank's beauty. Protect your fish and your tank with the NT Labs Methylene Blue.