Graham Ramsay Fair City Aquarist Society

Understanding the nitrification process is the single most important step to success in keeping fish

Nitrification is the conversion of toxic fish waste (Ammonia) into Nitrite then Nitrate

An aquarium is a “Closed System” – fish have to live in their own waste material – this is mainly Ammonia

Ammonia is a product of fish respiration and is excreted via the gills

Ammonia is highly toxic to fish – there is no safe level

The higher the temperature and pH the more toxic it is

Gill irritation – scratching and gasping at the surface Skin, eyes and gill damage Lethargy, loss of appetite Clamped gills, lying on the bottom Death

Bacteria consume the ammonia and excrete Nitrite

Nitrite is toxic to fish – there is no safe level

Ulcers, fin rot Gill irritation and lethargy Brown gills and respiratory distress Death

Bacteria consume Nitrite and excrete Nitrate

Nitrate is safe at low levels High levels encourage algae and weaken fish Very high levels are toxic to fish

Nitrate levels are kept in check by regular water changes

Bacteria live on surfaces – gravel, plants, filters Require food and oxygen

Keep filters clear – rinse in tank water

New tanks won’t have enough bacteria

Fish die when added to a new tank Fish excrete Ammonia and levels build up

Start with only one or two fish Feed very little Wait until bacteria build up

Consider starting your tank without fish Requires a source of Ammonia Levels need to be measured regularly

You can add fish when the process is finished Start with a few then add slowly

Happens when no water is changed Nitrate levels rise pH falls Water discoloured

Nitrifying bacteria die Ammonia is present but not toxic pH may crash

New fish added die quickly – shop blamed Existing fish seem fine

Sudden water changes raise pH Ammonia becomes toxic again

Regular water changes Keep filters clean

Fish excrete toxic waste Bacteria convert it to nitrate Remove nitrate by doing water changes

New tanks don’t have bacteria Start slowly – without fish if you can

Don’t forget your water changes!!!