Bermuda Banish Tap water Chemicals is the perfect way to protect your pond fish from the chemicals found in tap water such as chlorine. These chemicals can be harmful to delicate pond fish and can damage their gills and skin. Keep your pond water safe and allow your fish to thrive. Safe for fish and pond plants and pet and wildlife friendly. 250ml will treat a pond up to 5682 litres/ 1250 gallons in size.