One of the most fundamental needs to establish and maintain a healthy tank, is water quality. Basically, there are only three types of water, new, established and bad.
New water is the water which is initially placed in the tank.
Mainly all anyone can do when adding new water is to make sure the water is free from chlorine and chloramine. These chemicals are used to purify our drinking water by killing off any living organisms in the water before we try to drink it. Well, fish are just little living organisms which live in the water which are effected in the same manner as those organisms too small to be seen by the naked eye. There are many products on the market which will neutralize these chemicals to make your water safe for fish. Although this water is now safe for your fish, the water is still new.