CrystalClear WipeOut is safe to use for fish & plants when used to prevent and control many bacterial infections. WipeOut can be used any time your fish show signs of stress or bacterial diseases that can occur from poor water conditions overcrowding or abrasions from predators. CrystalClear WipeOut is perfect to use in ponds for both koi & goldfish but can also be used for common aquarium fish species. CrystalClear WipeOut is safe to use in ponds with fish and plants.