Tetra Ick Guard is a soothing conditioner that quickly clears ick (Ichthyophthirius multifiliis), or white spot, on freshwater fish. Ick is usually the result of sudden changes in the aquarium water temperature or stress. Left untreated, ick spreads rapidly, and is usually fatal. This fast, safe and effective remedy clears ick fast, and protects against secondary infections - no need to raise water temperature. These pre-measured Fizz Tabs dissolve fast to make caring for your aquarium easy. Add one tablet to each 10 gallons (40 L) of aquarium water. For aquariums 40 gallons or larger, and for soft water and/or acidic water with low alkalinity, dissolve tablets before adding to aquarium. Use Tetra EasyStrips™ to monitor pH and alkalinity levels. Use half-strength for scaleless or sensitive fish. If ick persists, treat every 24 hours until it clears. See product label for complete directions for use. Since 1951, Tetra has developed the world’s most comprehensive body of fish food knowledge, and fishkeeping enthusiasts have looked to the brand for products and solutions that add ease and beauty to their home. Whether you're an experienced hobbyist or just starting out, Tetra has everything you need – from a large variety of quality fish food and innovative equipment to test kits and decor.