Kordon Pond Rid-Ich+ is a combination of two powerful chemical medications (Formalin & Malachite Green) which have been proven to be effective in the control of many diseases of fish. Successfully treats disease caused by single cell parasites called protozans such as freshwater Ichthyophthirius (ich) Costia Trichodina Oodinium (velvet) Chilodonella and saltwater Cryptocaryon (Ich) and Amyloodinium. Rid-Ich will not interfere with biological filtration. 16 oz bottle treats 1920 gallons.