Nitrifying bacteria

From The Aquarium Wiki
Jump to: navigation, search
Mycobacterium tuberculosis1.jpg

Nitrifying bacteria is a term used to group species of bacteria that do useful work in an aquarium in turning toxic forms of nitrogen dissolved in water (typically ammonia (NH³/NH4) and nitrite (NO²)) into other forms of less toxic nitrogen (typically nitrate NO³).


Nitrosomonas Species: These are the ones that convert ammonia (released by rotting fish or plant waste) into Nitrite.

Nitrobacter sp.[1] and Nitrospira Species: They convert the nitrite into nitrate. Both of these are usually present in the filter.

  • Nitrosococcus and Nitrococcus are the main nitrifying bacteria used in salt water aquariums.

Growth Needs[edit]

  • A water temperature of around 20-30°C (68-86°F)
  • A water ph of 7.2-8
  • The water must have a KH and a GH of at least 6d (107.2ppm).
  • A nitrogen food source. Preferably free Ammonia (NH3)
  • A good supply of oxygen in the water. At least 3ppm.

Growth suppressors[edit]

  • Light. Nitrifying bacteria prefer to grow and operate in the dark.
  • Heavy metals and chemical metal chelators or binders slow growth.
  • High levels of NH3 (above 3ppm) suppress the bacteria's growth.
  • Lack of suitable surfaces to grow on. Bacteria prefer rough, high surface area surfaces. See Seachem's Matrix product.
  • Denitrifying Bacteria: This is the term used for a range of anaerobic bacteria that feed off oxygen from nitrate and work in conditions where there is no free oxygen to use. (In cases, they can turn nitrate back into nitrite).

Commercial Bacteria[edit]


  1. Dr. Tim Hovanec claims that it is Nitrospira sp. and not Nitrobacter that is the primary species for converting nitrite into nitrate. See PDF Paper.