Water Quality - Koi Care

Water quality is a very important aspect of Koi keeping. It is essential that perfect water quality be maintained in order for your Koi to thrive. If a pond is under filtered, then the Koi and other fish in it will suffer. The four most important water quality parameters are explained below:


Ammonia (NH3)

Humans and other mammals usually convert Ammonia into carbamoyl phosphate with the enzyme carbamoyl phosphate synthase and then it is either used or expelled by various means. However, Koi and other fish lack the mechanism so they excrete it directly into the water.

More on Ammonia Here.


Nitrite (NO2-)

Nitrite is formed in the second stage of the Nitrogen Cycle. It isn't as toxic as Ammonia, but long term exposure can cause problems.

More on Nitrite Here.


Nitrate (NO3)

Nitrate is a by-product of the Nitrogen Cycle, which is the process in which bacteria convert the toxins that Koi produce into non-harmful substances. The bacteria, Nitrobacter, converts the toxic Nitrite into Nitrate.

More on Nitrate here.




pH is the measure of active free floating Hydrogen ions in water. A pH level of 7 is neutral, a pH level below 7 is acidic and a pH level above 7 is alkaline.

More on pH levels here.


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