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 & can damage their gills & skin. Keep your pond water safe & allow your fish to thrive. Safe for fish & pond plants & pet & wildlife friendly. 500ml will treat a pond up to 11365 litres/ 2500 gallons in size.