How to temperature match your new tank water

Adding cold or hot water during a water change can shock fish. Match new water to within 1–2 °F of the tank. Use a thermometer, add dechlorinator, and heat or cool the water in a bucket before adding it. For Python-style systems, match at the tap.

Our full guide covers bucket methods, Python systems, and acclimation for new fish. See also water change frequency and acclimating fish.