water

Water is the medium in which fish live. How many people need to live clean air, so the fish need a clean water. In nature, almost never find a completely clean, so. distilled water. From the moment when the rain falls on soil, water changes its chemical composition depending on the area where it is located. So they are in different areas, fish and plants adapted to a different chemical composition of water. It should be noted that the vast majority of fish that are sold in the shops over several generations adapt to the water of our region. Of course this is not the case with all types so you need to ask before you buy fish. It is possible to artificially alter the chemical composition of water. It certainly would not recommend beginners aquarists, because a small error can lead to catastrophic results.  The most important thing is to maintain a constant chemical composition of water. Vast majority of fish that will be sufficient.