Is My Aquarium Cycled? ( 6 Signs of a Cycled Aquarium You Need To Know)

Most people love fish. As a result they will install the aquarium and fill them with fishes immediately But that is not enough because the fish tank needs to undergo a cycle called aquarium cycle.

If you don’t know the aquarium cycle you might kill your fishes as soon as you set up the new aquarium. So to avoid it, Let’s learn about the aquarium cycle and related questions on it, to save your aquarium livestock such as fishes and other aquatic animals.

Is My Aquarium Cycled? Yes, Only if there is a conversion of ammonia into nitrite, then nitrite into nitrate is taking place in your tank. While also there is a concentration of ammonia and nitrite shows 0 ppm in frequent tests. 

What is an Aquarium Cycle?

An aquarium cycle is scientifically known as the nitrogen cycle, this is the process or cycle where the fish food is converted into fish waste that turn into toxic chemicals such as ammonia nitrites and nitrates that are dangerous to fish itself as it swims through this medium. Thus it has to be eliminated or filtered through some means such as aquatic plants, nitrogen bacteria, etc. For example, some of these toxins are simply taken by plants to produce food that may again be eaten by plants thus starting this process again and again gives its name nitrogen cycle or aquarium cycle. 

The fish thrives in these cycles because there is constant or continuous elimination of waste and toxic substances. However, This nitrogen cycle does not occur in a new aquarium as it requires time for the formation of nitrogen bacteria to form in the new tanks.

Stages of an Aquarium Cycle:

1. Occurrence of ammonia- (a highly toxic substance): The excreta of fishes, the rotting food of fishes, the decaying leaves etc broken down or converted into substances called Ammonia, that is, highly toxic in water, especially for fishes as these swim, breathe, in these toxic substances. 

The concentration of Ammonia 0 ppm is a sign of it being converted into nitrites as soon as it is produced.

2. Occurrence of nitrites- (a toxic substance): The Ammonia now converted into a substance called Nitrites that are still toxic to handle by the Fish. The concentration of Nitrites 0 ppm is a sign of it being converted into nitrates as soon as it is produced.

3. Occurrence of nitrates- (a toxic substance): Now the nitrites are converted into nitrates that are somewhat toxic but not harmful as the ammonia and nitrites. The concentration of Nitrates below 20 ppm is a sign of it being eliminated from the water as soon as it is produced.

4. Elimination of Nitrates: The removal or elimination of these Nitrates are easy than the ammonia and nitrites, that is, it can be eliminated by plants in the aquarium or by the bacterias on the gravel, filter, etc making the aquarium water free from all harmful and toxic substance thus providing suitable water for fishes to swim, breath, or simply to thrive.

Why is an Aquarium Cycle Important? An aquarium cycle is important because this eliminates or converts the waste excreted by fishes, rotting food, decaying leaves etc. that are highly toxic to fishes into the less toxic substances and again into the less harmful substances. Thus an aquarium cycle keeps the tank water free from wastes, toxic compounds, etc. as a result the fishes can swim, breathe and live healthily in toxic free water.

How long does it take for a Fish Tank to Cycle? Naturally it takes about six to eight weeks or 42-56 days for a fish tank to reach a cycle. However, you can speed up the cycle by using some methods such as adding nitrogen bacteria, substrate, medium from nitrogen cycle established tanks. 

How do I know if my Tank is Cycled?

Testing the concentrations of ammonia nitrite and nitrates in the water, that is, If the concentration of ammonia and nitrite shows 0 ppm your tank is cycled that implies less toxicity to fishes as there is no concentration of ammonia and nitrites.  

The nitrates concentrations should be below 20 ppm, this shows that there is no toxicity for fishes due to the presence of nitrates. If there is more than 30 ppm of nitrates concentration you should either change the water to remove the nitrates immediately or install the substrates, rocks or plants from the matured, old aquarium to this aquarium so that the nitrates are converted into the nitrogen gases that are not harmful.

6 Signs of a Cycled Aquarium: 

1. There should be less concentration of Ammonia and Nitrites:

The pH levels in your aquarium below 7 indicates increased concentrations of ammonium than ammonia. Here, In this stage the concentration of ammonium is more and those are unable to convert into nitrites by the Nitrosomonas bacteria.

The pH levels in your aquarium above 7 indicates increased concentrations of ammonia than ammonium. Here, In this stage the concentration of ammonia is more that is easy to convert  into nitrites by the Nitrosomonas bacteria. This increases the population of Nitrosomonas bacteria as it gets the ammonia for feeding to them that causes the release of byproduct nitrite compounds.

2. The concentration of ammonia and nitrite should be around 0 ppm:

Both ammonia and nitrites are toxic to fishes; it has to be converted further into nitrates that is less harmful but it still has toxic effects.

Nitrites are converted into nitrates by the Nitrobacter, Which makes the concentration of nitrite and ammonia reach 0 ppm. When the concentration of nitrite and ammonia attains 0 ppm indicates that your tank is almost attaining cycle but not yet because nitrates are also little toxic that has to be removed.

3. Nitrates concentrations should not be above 20 ppm:

The Nitrates are also toxic to fishes but the nitrates toxicity is less when compared to nitrites and ammonia. This nitrates has to be eliminated in order to make its concentration less than 20 ppm. This elimination of nitrates can be done in many ways but easy methods are as follows.

4. Elimination of nitrates by replacing partial water of the aquarium(direct nitrates elimination):

We can remove old aquarium water containing nitrates in it and add dechlorinated water into tanks, that is, 20-40 % water replacement  between 1-3 week.

5. Elimination of nitrates by installing plants in the aquarium(a natural way):

We can remove old aquarium water that contains nitrates in it by installing aquatic plants as the plants use the nitrates for their own growth and developments help in the elimination of the nitrates. 

6.Elimination of nitrates by installing live rocks in the aquarium(a natural way):

We can remove old water containing nitrates in it by installing the live rocks, as the sea rocks contain anaerobic and  denitrifying bacterias that convert the nitrates into the nitrogen gases which is not at all harmful to aquatic creatures.

Read more : Difference Between Aquariums vs Terrariums

How can I speed up my Cycling Tank?

We can speed up the aquarium cycle in many ways, few are listed below:

Add the nitrogen bacteria from the old tank to the new tank: The nitrogen bacteria are present in substrates of old tanks such as rock, filter media, gravel, etc. once you manage to find the healthy old tanks you can transfer these substrates into your tank so that the bacterias are readily available for speeding up the process of nitrogen cycling in your new tank. 

However, This method has drawbacks as it can contaminate your new tank by the pathogens that are taken from the old tank through substrate thus can lead to stress and diseases.

Transfer the plants from the old tank to the new tanks: In a mature or old aquarium, the same nitrogen bacteria are also present on the plant surfaces. When we transfer them to the new tanks it can be helpful in establishing and maintaining the nitrogen cycle in the new tank.

Artificially add the nitrogen bacteria: There are many products readily available in the market which all contain the many kinds of nitrogen bacteria to start the nitrogen cycle in your new aquarium tanks. When we add these bacterias they will convert the ammonia into nitrites that again into the nitrate thus helps in the fast attainment of nitrogen cycle in new tanks.

How to know when a Tank is Cycled?

By testing the concentrations of ammonia nitrites, and nitrates you can know whether your tank is cycled or not. You have to use the pH level testing kits, nitrogen compound concentration testing kits etc. to  know whether a nitrogen cycle is occurring or not in your aquarium tank.

Your tank is cycle if it shows the following parameters:

  • The ammonia and nitrite concentration should be around 0 ppm: This indicates that the toxic substance such as the ammonia and nitrites compounds produced due to the excretion of the fishes and rotting foods are being turned into other forms that are usually nitrates.
  • The nitrates concentration should not exceed above 20ppm: If aquarium water contains the nitrates below 20 ppm it is a sign that almost the process of nitrogen cycle is occurring. The nitrates concentration under 20 ppm is possible by adding natural plants, other substrates from the health tanks as the substrates carry the nitrogen bacteria that precede the nitrogen cycle.
  • The appearance of algal blooms is the indicator of non-cycle or incomplete cycle: Algal blooms appear in the water medium that are rich in minerals and compounds such as the nitrates. Thus algal blooms is the sign for your tank is not undergoing nitrogen cycle.
  • The sick, stress, diseased fish are signs that a tank is not undergoing cycles: The excreta of fishes, rotting foods, decaying leaves produces ammonia that is very toxic to aquarium livestock such as fishes, snails, etc. These toxic substances make the fishes stress, prone to diseases, inactiveness, etc. This is also a sign for an aquarium that is not undergoing cycles regularly.

What happens if you Don’t Cycle your Tank?

In the absence of nitrogen cycle your aquarium tank water is keeps on deposited by the biowaste or bioload , that is, the excreta of fishes keeps on accumulating along the rotting food and decaying leaves as a result the concentration of ammonia, ammonium, etc increases. These ammonia, ammonium, nitrites etc are all highly toxic for fishes that can cause stress, diseases, death to these aquatic creatures.