Water
Tap water, chlorine and dechlorination
Water that is safe to drink is not automatically ready to put straight into a fish pond.
Know your supply
Chlorine and chloramine are used in water treatment. Do not assume leaving water standing removes every disinfectant. Choose a product or filtration system that specifically addresses the supply you have.
Follow the label
Dose for the appropriate volume using the manufacturer’s directions. Check whether a conditioner affects water-test readings and whether it is compatible with anything already in the pond.
Think about more than disinfectant
Replacement water can differ in temperature, pH and mineral content. Large changes need planning even when dechlorination is correct. Keep the hose clean and away from chemical contamination.
Build it into the routine
Keep the conditioner and a way to measure water volume available before starting maintenance. Never leave filling unattended. If you suspect untreated water reached the fish and they show distress, seek prompt expert advice.
Know the product you are using
Save a photo of the conditioner label and keep a record of your measured fill volume. Check expiry and storage instructions on the actual product rather than relying on a remembered dose from a different bottle.
Sources & further reading
Original WakeyKoi wording, informed by the references below. Linked clinical resources explain the evidence and their scope; they have not reviewed or endorsed this website.
Related guides
Educational guidance cannot diagnose an individual fish. Breathing distress, severe injury or unexplained losses need prompt professional assessment.