Can I use tap water for my freshwater aquarium, and if so, how should I treat it?

Yes, you can use tap water for your freshwater aquarium, but it must be treated to remove chlorine, chloramines, and heavy metals. Use a water conditioner designed for aquariums, and let the water sit for at least 24 hours before adding it to the tank to allow chlorine to evaporate. Always match the temperature and pH of the new water to that of the aquarium to avoid stressing the fish.