Mardel Sentry ProtoShield Freshwater/Saltwater Aquarium Treatments, 4-Ounce Natural Oil and Extracts provide relief from unwelcome parasites Protein stabilizer promotes penetration of the oils into the cell structure of the fishes skin The Biosphere Technology causes the treatment package to be covered with a shield to maintain contact Treats Protozoan Velvet; Trichodina Parasites; Ick-White Spot Treats 590 gallons