Many fish holders believe that if the water is not green or brown, fish can live in it. They might get this misconception from the fact that raw areas of water could occasionally appear polluted, but fish thrive there. However, raw areas of water embody their own customs for providing fish the circumstances they need while taking out harmful substances. Your tap water might be safe to drink, but it is not safe for fish to live in. Faucet water has chlorine, iron, and likely small amounts of lead and copper. Faucet water can also be too hard or soft for your fish, or consist of an abnormal pH. Luckily there are options to make your tap water suitable for a fish aquarium, as well as other water possibilities.
If you decide to use tap water the initial thing you need is something to remove the chlorine. All fish shops will have bottles of an item that you can put in the water to remove the chlorine, and they commonly last a long time. With the chlorine gone, your water will probably be safe for your fish, although you should also examine the levels of copper, lead, and iron in the water. These items are okay for you to drink in very little doses, but fish are much more easily harmed by them. You should also test the alkalinity and pH of your water to be sure it is okay for the fish you intend on keeping. You can also buy items to increase or decrease your alkalinity and pH determined by your wants.
Your other two choices are to obtain pretreated water for your aquarium, or gather rainwater. Purchasing pretreated water is the most pricey option, however it helps you be sure that the water will be prepared properly. This is a good choice when preparing a saltwater aquarium. Rainwater is rid of chlorine and metals and is especially harmless for fish. While contaminated rainwater has gotten a lot of press, it is indeed very rare and you can tell if the water is contaminated without testing it. Rainwater is, after all, what the native fish live in.
No matter which water you apply you will have to maintain it. Fish excrete waste that has ammonia. Incidentally naturally occurring bacteria in the aquarium convert the ammonia into nitrite, however nitrite is still dangerous to fish. Additional bacteria changes nitrite to nitrate, which is considerably less harmful. Incidentally this cycle helps an aquarium accomplish equilibrium, there are still cases to test and change your water. The ammonia creation of your fish can surpass the capacity of the bacteria to process this. This is usually the case with new aquariums that do not yet have enough bacteria in the aquarium. The ammonia production also increases any time you add new fish or increase the amount you feed them. Additionally, nitrates are still dangerous to fish in big doses. You should test your water and change it often to assist in keeping ammonia, nitrites, and nitrates in check.