The Nitrogen Cycle of a Freshwater Tropical Fish Aquarium

Now that the tank is running smoothly, theThe second way and the one I have used is to
temperature should be around seventy-eightadd fish. I started with six neon tetra and a
degrees. I would suggest adding two productscouple silver-tip tetra. Danios are hardy as well.
that I use in my tank to aid in the breakdown ofThis is quicker but remember ammonia and
waste and improve cycling. They are callednitrites are deadly to fish and this can kill them.
"Cycle" and "Waste Control" from Hagen. I haveDaily water tests must be conducted and water
been using them since day one and they workchanges preformed if the levels climb to high.
wonders.Water testing is a very important part of having
OK time to use our test kit to test severala freshwater tropical fish aquarium. If we don't
components of your aquarium water. We will testknow what the water is doing we will not know
the "PH", "Nitrites", "Nitrates", "Ammonia", "Iron",why we have cloudy water, our plants and fish
"Phosphate", "Carbonate Hardness" and "Generaldie or maybe algae is growing. Earlier in the article
Hardness". There are several different testI listed the main items that needed to be tested
chemicals out there but I use the Hagen test kitsfor. I will now give you the range that each should
and find them very reliable. You're saying tobe on average for a community tank.
yourself, I don't have any fish in the tank, why* The PH of my tank is generally in the range of
test the water.7.0 to 7.6. It is more important to have a
The simple answer is we need to know whereconstant PH rather than the so-called ideal PH.
the water is because in order to get a nitrogen* Nitrites should be kept below .3 mg/L. Nitrites
cycle going and for it to complete a cycle, fishare toxic to fish so if the nitrites climb above this
need to be introduced. Before we go on I willlevel do a minimum 20% water change.
take the time to explain what a nitrogen cycle is.* Ammonia should be kept below 1.2 mg/L. If the
Nitrogen cycles happen continuously in nature onlevel is above this mark follow the instructions in
it's own, but in a Freshwater Tropical Fishthe test kit to determine the level of toxic
Aquarium ecosystem we need to control it.ammonia and if a water change is necessary.
In stage one, ammonia is produced in the* Nitrate levels should not climb above 50mg/L.
aquarium via tropical fish waste, dead plants andLevels above this will contribute to the growth of
uneaten food. This waste will break down intoalgae. I try to keep my levels around 25 mg/L as
either ammonium (NH4) or ammonia (NH3).this supplies the plants with food but not enough
Ammonium is not harmful to tropical fish butfor algae growth. There's a fine line between the
ammonia is. If the PH is under seven, you willthe balance of nitrates with the number of plants
have ammonium. If the PH is seven or higher youin the tank.
will have ammonia. Most home aquariums unless* Phosphate levels should remain below 1.0 mg/L.
they are home to fish that need low PH will bePhosphates are a result of poor maintenance or
above seven.overfeeding. If the levels climb above 1.0 mg/L do
In stage two, bacteria called nitrosomonas willa 20% water change.
develop and they will oxidize the ammonia in the* Iron levels should be kept as close to .1 mg/L
tank, essentially eliminating it. The byproduct ofas possible. Iron is a necessary element if you
ammonia oxidation is Nitrites. Nitrites are just ashave live plants in your freshwater tropical fish
toxic to tropical fish as ammonia.aquarium. A lack of iron will result in poor plant
In stage three, Bacteria called nitrobacter willgrowth and even plants dieing. Excessive levels of
develop and convert the nitrites into Nitrates.iron on the other hand is toxic to fish. A case
Nitrates are not as harmful to tropical fish aswhere more is not better.
ammonia or nitrites, but nitrate is still harmful in* Carbonate hardness should be kept at or slightly
large amounts. The quickest way to rid yourabove, 80 mg/L. Carbonate hardness (commonly
aquarium of nitrates is to perform partial watercalled alkalinity) is the capacity for the water to
changes.neutralize an acid. I maintain a level of 80 - 90 mg
A new Freshwater Tropical Fish Aquarium withoutL.
anything in it will not start a nitrogen cycle on it's* General Hardness is the hardness of your
own. There are several ways to start a cycle butwater. A level of 40 - 80 ppm with give you a
since this is a new setup I will will discuss the firstslightly hard water which I find works great in my
two. The safest and least expensive method is tocommunity tank.
add a few flakes of fish food every twelve hours.We now wait until the first cycle completes and
This replicates uneaten food which will decay andthe tank settles in and we are ready to start
become ammonia and the cycle begins. Themaintaining our tank. I will discuss this in my article
downside to this is approximately two moretitled Maintaining a Freshwater Tropical Fish
weeks without any fish.Aquarium.