Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Maturing an aquarium (Cycling)

Panda Apistogramma, Apistogramma Nijsseni
Apistogramma Nijsseni, Panda apisto.


What actually happens when you mature an aquarium?

It is bacteria which maintain a healthy environment for fish to live in. They are responsible for breaking down all organic waste and rendering it harmless. These helpful bacteria have to be encouraged to colonise a fish tank before it is used to house any fish or the health of the fish will be at great risk. This is a very common problem among new fish keepers and the condition is commonly known as "New Tank Syndrome".

Fish produce ammonia and are constantly releasing it into the water column, they also produce waste which various fungi and bacteria breakdown into ammonia, this ammonia then builds up in the water until it reaches lethal levels and kills the fish. To combat this problem we use a bacterial colony mainly housed in the filter which breaks down this ammonia into nitrite and then into nitrate which is RELATIVELY harmless.

The filter bacteria

The different species of bacteria involved in the process have different needs and they colonise the filter in stages. The first to make an impact are the bacteria which breakdown organic waste and produce ammonia. This leads to a rapid increase in the ammonia level in the water because there are no bacteria present to break it down yet. Once there is a good level of ammonia in the water the next group of bacteria begin to colonise the filter, these bacteria use the ammonia and produce nitrite. Nitrite is also extremely toxic to fish and when both ammonia and nitrite are present at high levels then the fish are unlikely to survive. Once there is a good level of nitrite present a third group of bacteria begin to colonise the filter, this group use the nitrite and produce nitrate which is the end product of the nitrogen cycle and is the least toxic. Nitrate levels are normally controlled by making regular partial water changes using nitrate free water.

Even when all the ammonia and nitrite are being dealt with by the filter bacteria the maturing process will continue for the next few months. Using the example of the three species of bacteria which turn waste into ammonia, then ammonia into nitrite and finally nitrite into nitrate is a very much simplified version of what really happens. There is a whole mini eco system at work involving virus, bacteria, protozoa, fungi, single celled creatures as well as flat worms. round worms and so on all of which play a part in breaking down the waste. This eco system takes a while to reach a balance and mature and so even after the tank appears mature and is holding a good fish stock, the maturing process will continue.

Once fully mature and well maintained a fish tank should have few problems.

What do I have to do in order to mature the aquarium?

When you fill the aquarium for the first time it will be relatively sterile. in order to help the process to begin you will need to add a source of ammonia.

Although the following methods differ in their approach they are all simply variations on a theme. Ammonia is added in some form, the bacterial colony grow and the tank becomes mature (cycled).

Method one (a) Most Recommended
The easiest and most simple way to mature any aquarium.

Use Waterlife's BioMature as instructed. This product contains all the ammonia that is required. Simply add the required amount on a daily basis until the nitrites reach between 5 to 10mg/l and then stop adding it. Keep testing the nitrite level which will remain stable for a while and then it will suddenly drop. Once it reaches 0mg/l the tank is matured. That's all there is to it.

People sometimes get a little confused with this and worry about the bacteria dying off if nothing is added while waiting for the nitrite to fall. Well, there is no need to worry because the bacteria remain healthy, there really is no need to keep adding more and more ammonia once the nitrite level is between 5 - 10 mg/l. You don't even need to measure the ammonia level. Tanks normally take around two weeks or less to mature using this method.

Cultures of the ammonia-oxidizing bacterium Nitrosomonas europaea were starved for ammonia (energy source) for up to 342 d. During this time the bacteria could keep the ability to respond instantly to ammonia

Ben-Gurion University of Negev

*Tip - work out how many drops of BioMature that you need to add and then count them out into a separate container, then draw the contents of the container in to a medical syringe and make a note of the amount. This way you won't have to count out the drops every day.

In favour
1, Very easy to do.
2, Only requires the nitrite to be tested.
3, Clean and efficient.
4, You remain in full control of the process.
5, No fish are harmed.

Supermarket ammonia is cheaper if you have several tanks to mature.

Method one (b)  An even faster method
If you have a mature fish tank already then taking about 1/3rd of the mature biological media out of the filter and incorporating it in the new system and then proceeding as laid out above to mature the tank it will be a much shorter maturing time, often less than seven days.

In Favour
1, Very fast

1, Requires access to a mature aquarium.

Method two - Ammonia from a bottle
Ammonia cycling  calculator
The internet method. Instead of using a purpose made product like the previous method this one uses supermarket bought ammonia. Ammonia is added until the level in the aquarium reaches 4mg/l. I don't know if 4mg/l is the optimum level or not but it is the level which is most often quoted.

Add ammonia as and when required to maintain a level of around 4mg/l. After a short time nitrite will begin to appear and the level will rise. Eventually the ammonia will fall to 0mg/l within a 24hrs period and sometime later the nitrite level will do the same. Once both are falling to 0mg/l within 24hrs the tank is matured and ready for fish.

In favour
1, Cheap (useful for a new fish house or large tanks).
No fish are harmed.
2, Clean.

1, The method has been changed and adapted by people who have based the changes on intuition rather than real understanding.
2, Ammonia is quite a nasty chemical to handle.
3, It is no cheaper if you only have one tank to mature since you will have a lot left over (wasted).
4, Requires that both ammonia and nitrite are tested regularly.
5, Constantly adding ammonia to maintain 4mg/l could actually inhibit the cycling process.

Method three - using rotting fish, meat or prawn
Meat, fish or prawns can be used to produce ammonia by placing a few of thumbnail sized pieces in the tank and leaving them to rot, they will need replacing periodically because they contain a finite amount of ammonia.

It will take a little while for the process to begin and it might be a few days before any ammonia can be measured, again using this method a level of 4mg/l of ammonia should be aimed for by either adding more or removing some of the ammonia source.

Keep adding new pieces of meat, prawn or fish so that the ammonia level is maintained, eventually the ammonia level will fall and the nitrite level will rise until it reaches a peak and then that too will fall.

Once the levels of ammonia and nitrite are at 0mg/l the tank is cycled. It should then be given a good clean to remove all the debris and then a partial water change before adding any fish.

In favour
1,  This method is more likely to produce a more complete cycle if done correctly.
2,  No fish are put at risk.

1, Using this method is more difficult because it isn't very controllable, the ammonia may end up being to high and slowing the cycle down or it may never reach a level which builds up a large enough colony of bacteria.
2, Dirty, the remnants of the ammonia source will need removing once spent.
3, Columnaris bacteria can grow on this material and it can cause illness to fish at elevated levels.
4,  This is one of the slower methods and may take considerably longer than other methods.

Method four - cycling with fish. *Not recommended
Cycling with fish is possible and it can be done without any risk to the fish. A large aquarium is the best option for this method because the initial stocking levels must be very low or the fish will be at risk. The fish will produce ammonia as soon as they are in the aquarium and as soon as ammonia is present the maturing process will begin.

The theory behind this method is that the ammonia levels will be kept dilute in a large volume of water with very low stocking levels and that the ammonia levels will begin to fall again before they reach a level which is uncomfortable to the fish.

Feeding has to be kept low and tank maintenance has to be good so that neither ammonia or nitrite levels never rise above 0.1 - 0.2 mg/l. A 50gall tank with around 3 or 4 small tetras would achieve this, a 12gall tank with two goldfish would not and the goldfish may not survive.

Stocking levels can be very slowly built up by adding a few new fish when no ammonia or nitrite can be detected until the desired stocking level is reached.

In favour
1, Fish are added to the tank relatively quickly.

1,  If to many fish are added at once then they are very much at risk.
2,  If it is done wrongly then it involves a great deal of cruelty.
3,  This is a very slow method when compared to the others.
4,  Only likely to work with large aquariums housing small fish.
5,  Both ammonia and nitrite levels have to be checked very frequently, water changes may be called for if the levels begin to increase to much.

Method five - maturing a planted aquarium
By planted aquarium I mean a specialist set up with CO2, special substrates and the right lighting levels for plant growth and most importantly - densely planted with healthy and actively growing plants.

I do NOT mean a normal aquarium with a few bunches of plants pressed in to the gravel.

The plants will take on the role of the filter bacteria to begin with by removing the ammonia from the water in order to use it for themselves. Lots of actively growing plants will have little trouble in doing this although there will still be enough left over for the tank to mature in the normal way, Quite often this is the only method to use on such a system because the plants remove the ammonia so efficiently that other methods of adding it will fail.

Fish stocks should be built up slowly in order to play it safe and to keep the fish healthy.

In Favour
1, Once the plants are settled in and growing, the fish can be added.
2, Generally a very safe method to use.
3, Fast.

1, Requires a specialist planted aquarium.

Marine aquaria

Live rock comes with an inbuilt supply of all the bacteria that is required, however, their numbers may need building up before fish are added. The recommended amount of live rock is 1KG/10L or 1lbs/gall. If possible use cured live rock because if new live rock is used there may be a large ammonia spike which could degrade the live rock, when cured live rock is used this won't happen to the same degree.

To cycle the tank with live rock simply add it at the required level and test the water and ensure that water is being pumped all around it with no static regions. To ensure a good flow try to aim for a minimum of pumping the volume of the tank ten times per hour. There may be a few small spikes initially but once these settle it is safe to add the first fish.

In favour
1, Looks very natural.
2, Lots of additional life will appear on and from the rocks.
3, Nitrate will be kept low using this method providing the tank is properly stocked.

1, The rock may harbour unwelcome guests like mantis shrimps and aiptasia or majano anemones.
2, Circulation pumps may be difficult to conceal and still work efficiently.
3, Expensive.


Will aquarium disease treatments affect the cycle?
Yes, although many products claim not to harm filter bacteria, most will set the cycle back a little if used. It is best not to use them in a maturing aquarium if at all possible.

Will the pH of my aquarium make any difference to the maturing process?
Yes, all the different species of filter bacteria thrive better in water which is slightly alkaline. Ideally pH 7.6 to 8.5 once mature the pH can safely be adjusted to suit the fish.

Does temperature make any difference to maturing an aquarium?
Temperature makes a tremendous difference. When the maturing process is going on if the tank is kept in the mid eighties F the process will be very much faster and the tank could mature in as little as two weeks.

Will adding ammonia to my tank occasionally help keep the filter in tip top condition?
Ammonia must never be added to a tank containing fish. It could kill them.