Water quality is affected by two main factors: firstly, contaminants (organic and inorganic) which it contains when drawn from the tap, and secondly those which enter it while it is in the aquarium. Both inorganic and organic contaminants are involved.
Inorganic contaminants
Tap water may contain small quantities of various metallic salts, either naturally or as the [...]

Much of the fun in keeping fish is to be found in their regular upkeep, the essential tasks that ensure that they are kept as healthy as possible. By carrying out these tasks according to a regular timetable (such as that provided here), the aquarist can be certain that all important aspects of maintenance are [...]

For most hobbyists the most exciting part of setting up a new aquarium is buying and introducing the fish. Even when the filtration is mature, there is some debate as to whether you should add your fish all at once or in small batches over the ensuing weeks.
With freshwater tropicals, if the ‘daily feed’ maturation [...]

It may seem silly to talk about hiking techniques. After all, everyone already knows how to walk, don’t they? But hiking up and down hills with a heavy backpack on requires some additional care. In town, walking on sidewalks, it’s safe to make certain assumptionsˇŞthe walking surface is generally smooth, and the curb is always [...]

It is estimated that at least 95% of aquarium ailments are environmental rather than pathogenic, that is, the result of something the aquarist has or has not done, rather than infectious causes. Unfortunately most aquarists find this fact unpalatable and choose to convince themselves otherwise, commonly making an already bad situation worse by misusing medications; [...]