Bacteria - its not all that bad

Hi Guys,

Maintaining an aquarium is straight forward when you look at the basics. Water changes, cleaning the filter, the glass and gravel each week. These are the basic chores a fish keeper is required to do to keep their fishtanks in tip top condition. Have you ever wondered why we use gravel? or why there are different types of media for your filter?

Most aquarium filters consist of a mechanical, Chemical and Biological filtration system, usually, sponges, ceramic or stone blocks plus carbon/charcoal bags.

  • Mechanical Filtration picks up the large waste like excess food or fish waste
  • Chemical Filtration removes decaying tissues that are present in tap water. 
  • Biological Filtration removes any ammonia or nitrate
It can sound a little confusing to new fishkeepers however, the modern filters are designed to do all the work for you.

I believe the Biological element of your filtration is the most important one. after all its alive. Some may say that swell as fishkeepers, we also look after colonies of bacteria at the same time. Looking after your filter is very important. If you keep your biological filter in good condition, it will do its job and keep your ammonia/nitrate levels in the safe zone.

What is the biological filter?

Your biological filtration consists of several different bacteria colonies. The two main and most active are called Nitrosomonas & Nitrobacter. These bacterias along with the others establish themselves in your aquarium. This diagram explains the entire process of the nitrogen cycle.

Each bacteria performs a specific task. This is vital to any aquariums good health.

Bacteria colonise your gravel, rocks, ornaments and even your glass. One of the great things about filters is they create habitats for the beneficial bacteria to colonise.

When an aquarium is first set up it is incapable of supporting any livestock until it has built up large enough colonies of beneficial bacteria to convert all traces of toxic ammonia and nitrites into nitrates which are then removed during water changes or consumed by plants that have been added to the tank. 

How do you establish healthy bacteria?
This diagram shows the process called the "nitrogen cycle" which is what most fishkeepers will state as the most important part of setting up your aquarium. Your aquarium goes through three basic stages.

  1. Ammonia is created by waste products - you can add a little food or even a fresh prawn or shrimp to an empty tank to create this. Ammonia consuming bacteria develops and consumes the ammonia
  2. Nitrite is formed as a byproduct of the ammonia being consumed. Nitrite is harmful to fish so enough time must be allowed to develop a secondary bacteria colony which consumes the nitrite.
  3. Nitrate is generated when the bacteria consumes nitrite. Nitrates  are easily removed by performing water changes. If you have added live plants to your aquarium, these plants will consume nitrates naturally.
The full cycle takes time and fish should never be added until your water perimeters indicate that the cycle is complete. This process normally takes around 6 -8 weeks. Regular testing of your water will keep you informed of its progress.

Its always advised to add sturdy fish first to a new aquarium. This is a good way to ensure your new tank establishes itself at healthy pace.

Is there a quicker way?
There are products on the market that can introduce these vital bacterias to your aquarium quicker than following the above method. You can add colonies of bacteria directly into your substrate prior to filling your aquarium. It is also possible to add trace elements and additional bacterias all aimed at maintaining a healthy mini ecosystem in your aquarium. When using these products it can be possible to add your sturdy fish within a few hours once your aquarium temperature is up to the desired level.

Just like the traditional method of cycling your aquarium, testing your water is very important to insure it is ok for the fish intended. Research your fish choice and insure you are providing the correct temperature, Ph and other perimeters. This will ensure you get the best out of your fish.

My thoughts are...
In my experience of using both these methods, I have had good results with both. If you are in no rush to set up your new aquarium and can allow for 6-8 weeks to pass before putting fish in then I recommend you use the tradition method. However, If you are in need of a quick set up and cannot wait that long, I can honestly say the quick start products will do the job. Just remember to test your water!

This is only my opinion on cycling an aquarium and I respect their is always other methods that can work so be sure to research and find the method that works for you. If you have any comments on how you cycle your aquarium, please comment below.

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Image courtesy of KasiaJB from

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