Poisonous substances in Aquarium water II

Apart from the Gas Bubble Disease (caused by atmospheric nitrogen) discussed previously there are some other nitrogen compounds which produce poisonous substances; these are Ammonia, Nitrite and Nitrate. They are all formed by the breakdown of proteins, and since they are produced in the aquarium itself small quantities are always present in the water under normal conditions.

Ammonia (NH3) is the most important end product released during the digestion of protein by freshwater aquarium fishes, it is released in the form of ammonium (NH+4). A small quantity of ammonia is also produced during the breakdown of proteins present in the urine and faces of aquarium fish and in food fragments. Both the ammonia and ammonium in the water are in balance according to the following chemical equation.

NH3 + H2O = NH4 + OH = NH4 + IS NOT HARMFUL TO FISH

The balance depends on the acidity (pH) and temperature of the water. When the pH is low together with a slight temperature like in a natural aquarium set-up using a split incandescent bulb lightening system; the NH3 LEVELS are low and NH4 + high. The reverse is the case in an artificial aquarium set using a white gravel base together with a fluorescent lightning system. Here the water is alkaline due to the increase in calcium carbonate (cacos) released by the gravel, the resultant high pH (hydrogen-ion concentration) together with low temperature usually result, in a high NH3 level which normally cause the popular Acute Ammonia Poisoning disease (AAPD), which is usually rampant among fishes kept in aquariums using a completely white gravel bed.

Solution to Ammonia Poisoning disease in aquarium water

The disease could be cure by a breakdown (oxidation of the ammonia by Bacteria in the aquarium itself or more effectively by a biological (undergravel) filter through the process called Nitrification as shown below:

Ammonium (NH4+) Nitrite (No2) Nitrate (No3). The interproduct, Nitrite is also very poisonous to fish, because it oxidizes the red blood pigment (heamoglobin to methaemoglobin) to a compound that cannot transport oxygen hence aquarium fish could suffocate.

Then end product, Nitrate is 2000 times less poisonous than nitrite relatively harmless to fish.

Poisoning by Ammonia or Nitrite can be avoided by maintenance of good quality aquarium water based on the natural system.