Goldfish Nitrite and Nitrate Poisoning

Nitrite Poisoning



Cause: Nitrite poisoning often occurs after ammonia poisoning. Nitrite is absorbed into the goldfish through its gills and then attaches to the red blood cells in the goldfish’s blood stream. This condition called met-hemoglobinemia or ‘brown blood disease’, makes the blood cells unable to carry oxygen. The goldfish will eventually suffocate and die from a lax of oxygen. Goldfish that are exposed to even low levels of nitrite can make them more susceptible to other disease like ich fin rot or bacterial infections.


Symptoms: The symptoms of nitrite poisoning include: listlessness, gasping at surface, brown gills, rapid gill movement, brown blood and upon death, the goldfish will have flared gills.


Cure: Reduce the nitrite levels in water by reducing feeding for the time being and removing goldfish waste, debris and materials that contains nitrogen. Preform a large water change of 50-75%. Adding a .03% aquarium salt solution will inhibit nitrites from absorbing into the goldfish through its gills. Make sure the goldfish tank is well oxygenated by adding an air bubbler or airstone.


Prevention: Add new fish slowly, keep waste and debris out, preform routine water changes.




Nitrate Poisoning



Cause: High levels of nitrates in the water gets absorbed through the gills. This occurs in new tanks that have not cycled yet or when new fish are introduced.


Symptoms: High nitrate levels cause blood vessels in the fins and skin to become dilated making the skin to appear streaky, Inactivity, listlessness, loss of appetite Goldfish exposed to low levels of nitrates over an extended period have a lower immune system, making them more susceptible to other goldfish illnesses like ‘flipover’.


Cure: Work at getting nitrate levels bellow 50ppm by adding aquatic plants, allowing some algae to grow, and doing routine water changes.


Prevention: Allow the biological cycle to become established and add new fish slowly. Remove any waste and debris from the goldfish tank and preform routine water changes.






photo credits: bensonkua