Actually, you shouldnt use tap water straight out of the faucet. If you're going to use tap, make sure you either let it sit for 24 hours, OR, if you want to use it immediatly, get it into a coantiner and add Stress Coat to it (you can buy this at pretty much any pet store that sells fish products) Tap water has a lot of chemicals added to it that help us, but hurt fish. Any other type of bottled H2O or bottled water at fish stores is okay