Advanced hobbyists will seek the highest quality, most effective products to treat fish illness. The new API PRO SERIES powdered medications deliver. This comprehensive line, containing USP-grade antibiotics offers superior performance to treat a broad range of ornamental fish disease. In addition to their high quality ingredients, they include detailed disease illustrations on the front of each package, as well as symptoms description, in a diagnostic chart on the back, to aid in diagnosis. Treating fish disease has never been easier. Furan-2 contains two furan compounds to combat a wide variety of gram-positive & gram-negative bacterial diseases, including gill disease, mouth fungus, furunculosis (aeromonas), black molly disease (columnaris), fin & tail rot and dropsy. Each powder packets treats 10 gallons of water. Four doses required for full course of treatment. For Fresh and Saltwater aquariums.