Melafix is an all natural, botanical medication. The patented formula uses the healing power of Melaleuca, or tea tree extract, to rapidly heal bacterial infections in Koi and Goldfish. Tissue regrowth can often be seen within 4 days of treatment. Will not affect the biological filter or alter the pH of the pond. - Treats ulcers, open wounds and fin and tail rot - Rapidly repairs damaged fins - Use when introducing new fish - Safe for aquatic plants - Treats up to 19,000 gallons