What is the nitrogen cycle, & how to quickly cycle your aquarium with or without fish using bio media?

You cannot avoid the Nitrogen Cycle if you want to keep fish in your tank. It is important to learn this cycle so that your fish can enjoy a happy & healthy environment. The cycling process takes from two to six weeks. The 3 main toxins in the tank are ammonia, nitrites & nitrates so the nitrogen cycle must work effectively to eliminate these toxins.

Biological filtration helps in speeding up nitrogen cycle. Biological filtration is most important in all types of filtration. Your fish could die if the tank is not properly maintained. For understanding nitrogen cycle, it is important to learn about frequently asked questions added below:
  • What is the nitrogen cycle?
  • How does the nitrogen cycle work?
  • How to perform a nitrogen cycle?
  • How to cycle an aquarium with fish?
  • How to cycle an aquarium without fish?
  • How biological filtration helps in speeding up the nitrogen cycle?

What is the nitrogen cycle?

Nitrogen cycle is a process that includes the continual circulation of nitrogenous compounds including ammonia, nitrites & nitrates to process wastes in the water. It is very important for a tank to establish this cycle.

It is advisable to develop your new tank slowly over time, & with small fish nitrogen cycle will gradually remove waste particles. The beneficial bacteria takes time to produce in a newly established tank & it is not recommended to put the large beautiful fish in your tank. Also do not overfeed your fish. However, if there are not enough beneficial bacteria which build up in a tank over time, the possibility is many of the inhabitants will die.

If the dead fish are not removed quickly, their decay will put fish in a more dangerous condition & you may lose the remaining fish. It is recommended to cycle your tank first, add inhabitants gradually & do not overfeed them.

How does the nitrogen cycle work?

It is very important to learn the nitrogen cycle. The nitrogen cycle is very important for biological filtration. It will remove the dangerous compounds from your aquarium that are produced by the respiration of fish & it is also produced by the decay of fish waste & uneaten food. Learning about the nitrogen cycle will help in preparing in advance to cater these issues.

During the nitrogen cycle, the waste particles are broken down by bacteria & fungi into ammonia which is very dangerous for fish. Nitrosomonas is a good bacteria which consumes oxygen & ammonia, & convert them into nitrites which is less dangerous as compared to ammonia but still harmful & can kill fish even at low concentrations. Nitrobacter is additional beneficial bacteria which also consumes oxygen & it changes nitrites into nitrates that are less toxic as compared to nitrites. The bacteria which converts ammonia into nitrates is known as nitrifying bacteria. Another bacteria is used to eat nitrates which grows in oxygen free areas & needs low oxygenated still water. This beneficial bacteria (denitrifying bacteria) can be discovered in a more elaborative filtration system & inside live rock that converts nitrates into free nitrogen.

How to perform a nitrogen cycle?

Nitrogen cycle can be performed in a tank which already contains fish or it is preferable to perform nitrogen cycle in a fishless tank because this process takes up to 3 months to complete. During this process a lot of toxins are produced along with beneficial bacteria. Toxins are dangerous to fish & large amounts of these toxins can kill your fish. However, slowly & gradually beneficial bacteria is produced & it helps to provide an ideal environment for your fish. A happy tank needs to be fully cycled & it is very important to learn how the nitrogen cycle is processed & we have mentioned all the steps required to speed up the process & also you can monitor the levels of toxins that are produced during the nitrogen cycle. In the end it is advisable to test for all toxins & when they are removed, then add fish to your aquarium.

Do not buy an aquarium & fish at the same time. First buy an aquarium, run a nitrogen cycle & when the cycle completes then start adding fish to your tank. However, if you have already bought a tank & fish at the same time then we have also provided a complete guide to fully cycle your tank with minimum risk.

2 methods can be used to achieve nitrogen cycle:

  1. With fish
  2. Without fish

How to cycle an aquarium with fish?

I do not recommend this method but if you are in a hurry then I have provided all the instructions required to achieve it. However, if concentrations of ammonia & nitrites are too high then fish may die.

Your objective is to add fish to the aquarium. Also your aquarium must endure high levels of ammonia & nitrite levels for a longer period to grow good bacteria. Feed your fish once every 2 days. Offer them moderate food. If you overfeed fish, they will produce more waste. Also the food left by the fish will rot & generate even more toxins. Regular water changes will lower the amount of toxins & will make sure the levels of toxins do not exceed. The objective is to do 10-15 percent water change everyday. More changes will result in loss of ammonia & nitrite that good bacteria needs. Add de-chlorinator to the aquarium water. Chlorine can eliminate good bacteria & destroy the nitrogen cycling process. After the toxin level hits zero, then it is time to add more fish to your aquarium. Do this gradually & add 1 or 2 fish at a time. After you add them, test the water. If you find the levels of ammonia & nitrite low, add more fish.


It is necessary to perform this step slowly. Inclusion of many fish will rise the levels of toxins. 

How to cycle an aquarium without fish?

I strongly suggest using this method as it won’t stress or kill your fish. We have added a simple method to perform a fishless cycle.

Make an environment for the fish where ammonia is generated. If there are no fish in the aquarium, then use this method. An easy way to do this is to start by dropping food into your aquarium. The food you put in the aquarium should be of the same amount that you would add if you are feeding fish. Add food every 12 hours. Wait & the flakes will decay slowly & will be converted into ammonia. Test for ammonia using the test kits. If you do not find sufficient ammonia in the aquarium, add more food & allow them to decay. Do the same step every other day, & attempt to maintain the ammonia level at 3ppm. Nitrosomonas will start to expand after feeding on ammonia. You can refill them by adding more food whenever it drops below 3ppm. After a week, it is time to test the aquarium water for nitrites. Use a commercial test kit to perform this. When you notice nitrites in your aquarium, you will know the cycle has begun. Add more ammonia. After testing for ammonia & nitrites for a few weeks, you may notice that the levels of nitrites will begin to drop & now it is the time to begin testing for nitrates. After the ammonia & nitrite level reaches zero, the cycle is finished. But if you detect that nitrates level is over 40, there is a need for water change. If there is no ammonia or nitrites in your aquarium, then it is time to add fish to your aquarium.


Gradually add fish. Do not add more than a few fish at a time. Introduce more fish after waiting for a week or two.

How to quickly cycle an aquarium using bio media?

Biological filtration generates biological stability in aquariums by providing the ideal environment for beneficial bacteria. Beneficial bacteria can be produced by adding biological media to the aquarium. We are going to discuss 3 types of biological media that speeds up the process & allows good bacteria to grow. Biological media includes aqua one bionood ceramic rings, bio baki balls & premium sub ceramic substrate.

How to quickly cycle an aquarium using bio media?
How to quickly cycle an aquarium using bio media?

Ceramic noodles are extremely porous & build the ideal environment for growing beneficial bacteria. There are many little holes in ceramic media & all the beneficial bacteria grow here. Ceramic rings increase the surface layer through little holes inside it & offers more space for the beneficial bacteria to cling on & grow. They can hold both nitrifying & denitrifying bacteria. Pollutants like ammonia & nitrites are broken down into nitrates that are less dangerous & can be removed from the aquarium with regular water changes.

Bio baki ball is a breathing bio ball fired by extreme temperature. Bio baki ball is the best material for producing nitrifying bacteria. It helps restore the natural quality of aquarium water, & provides the ideal environment for your fish.

Premium sub is another bio-media which is subjected to extreme temperatures that creates thousands of tunnels through it. The porous material allows more beneficial bacteria to grow over its surface.

Post a Comment

Previous Post Next Post