Although tap water is usually a suitable substitute for a fish's natural aquatic needs, it does require certain measures to taken before it can be used in the aquarium. Water from our mains supplies have been treated in such a way that makes it safe for humans to drink. Chlorine is used in our water systems, which kills off bacteria and disinfects the water. There can also be metal contamination in tap water due to it transportation to homes through pipes-lines, copper for instance.
Chemicals added to our water supplies are potentially lethal to fishes. These chemicals can attack gills and the mucus membrane that covers and protects the fishes, making them vulnerable to bacterial and fungal infection. Heavy metals can also be found in our tap water, such as copper, lead, zinc, which are toxic to all tropical fishes.
It is therefore necessary to treat tap water before it goes into the aquarium. There are a number of manufacturers who make products that dechlorinate tap water, they usually contain other additives that also condition the water and coat the fishes with a protective barrier of Aloe Vera.
Regular monitoring of your aquarium water is essential. It is possible for harmful pollutants that cannot be seen, to enter your aquarium water without your knowledge. These pollutants can pose a great danger to your fishes, therefore the only way to be sure of its condition is to do regular water tests.
There are many tests that will indicate your waters condition and its properties; here I discuss the more important ones.
Ammonia/Ammonium Test:
Ammonia is very soluble in water; it is excreted by all fishes, and is extremely poisonous to them. A by-product of ammonia is ammonium, which less toxic, it is formed by the acceptance of a proton by an ammonia molecule, and is present at lower pH levels. Ammonia will become more toxic at higher pH levels, and to a lesser degree on the temperature. This test gives an early warning of a failing filtration system, probably due to overstocking of fishes, or over feeding.
Ammonia tests actually measure total ammonia; this is a combination of ammonia and ammonium. To properly determine the amount of toxic ammonia that may be present in your water, you will need to know its pH, and temperature to do the test. You can then compare the result of your test against the chart supplied with the test kit to determine if ammonia is present, and to what degree, the ideal result should be zero.
Nitrite Test:
Ammonia is broken down and converted into Nitrite by nitrifying bacteria, (nitrosomonas bacteria), although less poisonous than ammonia, nitrite is still very dangerous to your fishes. A nitrite presence usually means a bacterially immature or inefficient filtration system, possibly overstocking and/or feeding. This test will indicate what level of nitrite, if any is present. Levels above 1.0mg/L (ppm) for fresh water aquariums are considered unsafe; ideally, as with ammonia, readings should be zero.
Nitrate Test:
Nitrite is broken down and converted into Nitrate, this is the end product of the nitrogen cycle, and is used as a food source by plants and algae. Nitrate is relatively non-toxic, but if high readings are observed from your test result, it is indicative that a partial water change is necessary.
pH test:
As various fish species originate from different waters of the world, so the pH of those waters differ; it is therefore necessary to mimic those conditions the best we can. A pH test will indicate your waters acidity or alkalinity. Sudden changes of pH should be avoided; this causes stress to fishes, which lowers their resistance to disease, for this reason it is therefore very important that any pH adjustments be made gradually over a period of time.
Water Hardness Tests:
Most species of fish do not like hard alkaline water; some species however do live in such conditions and need hard alkaline water to survive. Under the wrong conditions fish species of any given type will fail to breed, be poorly coloured, and have a low resistance to disease. It is therefore necessary to determine what type of water you have in your aquarium for the sake of your fish's survival.
There are two types of hardness test, one to confirm its GH (General Hardness), and is a measure of all the dissolved salts in the water, these salts are principally composed of calcium (Ca) and magnesium (Mg). GH can also be termed as total hardness.
The other test is for Carbonate Hardness (KH) or temporary hardness, and is commonly referred to as alkalinity. It is a measurement of the capacity for water to neutralize an acid, and is known as the buffering capacity. Therefore water hardness is closely linked to pH.
