How To Cycle An Axolotl Tank [Cycling Guide]

If you’ve followed my Beginner’s Guide on How To Set Up An Axolotl Tank, you’ve already bought and installed everything you need to welcome your first pet axolotl.

But, there’s still one VERY IMPORTANT step you need to complete: ensure that the tank water is just right! When it comes to axolotls, water quality is perhaps THE most important aspect of your axolotl tank.

The final step in the setup process is to cycle your tank. You MUST make sure that your tank is cycled BEFORE introducing your pet axolotl.

In this guide, I will cover:

  • Nitrogen cycle of water.
  • Optimal water parameters for an axolotl tank.
  • Axolotl tank cycling.
  • Water testing.
  • Water conditioning.

If this sounds helpful to you, keep on reading below. Also, please consider sharing this guide on social media as it might help other people out too. Thank you!

Table of Contents

How To Cycle An Axolotl Tank (Tank Cycling Guide) Featured Image

Nitrogen Cycle of Water

In your quest for optimal water chemistry, you will be able to call on an important ally: beneficial bacteria – and nitrifying bacteria in particular.

Nitrifying bacteria enable what’s known as the nitrogen cycle of water. In summary, beneficial bacteria break down the most toxic compounds in the water (ammonia) into less toxic compounds (nitrates), which are then either removed from the water via water changes or absorbed as nutrients by live aquatic plants.

The nitrogen cycle of water is a topic in and of itself, too lengthy to cover in full in this article. Check out this resource for more details.

Nitrogen Cycle Water Axolotl Tank
The Nitrogen Cycle of Water in an Axolotl Tank

Optimal Water Parameters For Axolotls

The main parameters you will need to test and control are listed out below. I’ve also included target values for axolotl tank water to put you on the right path.


Optimal water temperature range: 60 to 64 degrees Fahrenheit (16 to 18 degrees Celsius). 

pH Levels

Optimal pH range: 7.4 – 7.6

pH is measured on a scale of 0 to 14 where 0 is the most acidic, 14 is the most basic/alkaline, and 7 is neutral.

As you can see, axolotls prefer a very slightly basic water pH.

Ammonia & Ammonium (NH3/NH4+)

Optimal ammonia concentration: 0 ppm (ppm stands for parts per million)

Ammonia is the major waste product of axolotls. It’s excreted through the animal’s gills, urine, and feces and is also a by-product of decomposing uneaten food or organic matter (dead skin, axolotl slime, plants, etc.).

Ammonia is extremely toxic to axolotls.

Nitrite (NO2-)

Optimal nitrite concentration: 0 ppm

Nitrite is produced when nitrifying bacteria break down the ammonia in your tank. Nitrite is highly toxic to axolotls, even at low concentrations.

Nitrate (NO3-)

Maximum nitrate concentration: 5 to 20 ppm

Nitrate is produced when nitrifying bacteria further break down the nitrite in your tank. Nitrate accumulates in your tank and is mildly toxic to axolotls. Nitrates are removed through regular water changes.

Cycling Your Axolotl Tank

At this stage in your build, you need to cycle your tank. Cycling your axolotl tank kicks off the growth of the nitrifying bacteria mentioned above. There are different ways to cycle a tank, some more complicated than others.

The method I will explain below is the most beginner-friendly method. It’s also sometimes called “instant cycling”, as the process is accelerated when compared with more traditional cycling protocols.

The instant cycling method relies on “seeded media”. Seeded media are filter materials such as sponges, meshes, bio-balls, or chemical rings that are pre-saturated with large quantities of beneficial bacteria which will immediately kick off the nitrogen cycle in your tank.

To feed these bacteria, liquid ammonia is added to the water. The bacteria will feed off the ammonia and proliferate into colonies large enough to balance the water chemistry once your axolotl is introduced.

Items You Will Need To Cycle Your Tank

Here’s a summary of the items you will need to instant cycle your tank.

Note: They’re included in the supply list summary section above. You can receive this list directly to your email by signing up below (the email also includes a printable PDF version).

  • Fully Set Up Tank (see section 2), including functioning filter.
  • Water Conditioners
  • Seeded Media – if available.
  • Bacteria Booster
  • Liquid Ammonia Solution
  • Water Test Kit

How To Cycle Your Tank

Step 1: Condition Water

Condition your tank water using water conditioners. Make sure to follow the instructions on the bottle. Conditioning will help dechlorinate the water and adjust the pH levels.

If the water has been in your tank for several days already, then a lot of the chlorine will have evaporated already so you won’t need to use as much conditioner.

Step 2: Add Seeded Media (Optional)

If you’ve managed to get your hands on seeded media, insert the seeded media into your filter and switch on the filter. Otherwise, skip to step 3.

It’s worth noting that you may not be able to find seeded media or media that’s 100% compatible with the exact filter model you have. You may need to adjust the seeded media so that it fits into or onto the specific filter model in your tank.

Alternatively, you can simply submerge the seeded media next to your filter inlet or outlet, so that the water cycles through it indirectly.

Step 3: Add Quick Start Bacteria Booster

Add the API Quick Start bacteria booster to the tank water, following the instructions on the container.

Step 4: Add Liquid Ammonia

Add the liquid ammonia solution to the water in quantities such as to achieve a concentration of 2 to 4 ppm.

You will need to carefully read the instructions here to make sure you’re dosing the solution out correctly for the volume of water in your tank.

Step 5: Let Your Tank Cycle

Let your tank cycle for 7 to 10 days by keeping the filter and light switched on. The light will provide an extra boost to the bacteria’s growth.

During this step, the bacteria from the seeded media and bacteria booster will begin to break down the ammonia, kicking off the nitrogen cycle. In doing so, nitrites and nitrates will begin to appear in your water during testing.

Step 6: Test Your Water & Monitor Parameters

Using your test kit, take daily readings of the ammonia, nitrite, and nitrate concentrations. Keep a record of these so you can gauge their evolution over time.

Once the nitrogen cycle kicks off, the following will happen:

  • Ammonia levels will drop (a good sign, it’s being broken down by the bacteria).
  • Nitrite levels will increase (nitrite is a by-product of ammonia breakdown).
  • Nitrite levels will drop, and nitrate levels will increase (the nitrite is itself broken down by the bacteria, resulting in nitrate).

You will know that your tank is fully cycled once you achieve the following parameters:

  • Ammonia: 0 ppm
  • Nitrite: 0 ppm
  • Nitrates: 5 to 20 ppm

Step 7: Adjust Ammonia

The aim at this stage of the cycling process is to achieve a concentration of nitrates of 5 to 20 ppm. Once you’ve hit this milestone, you’ll know that the bacteria colonies are large enough to break down the waste that your axolotl will produce once introduced.

If the nitrate concentration is any lower, your bacteria colonies are still too small. In this case, you will need to keep feeding them to make them grow bigger. And how do you do that? Well, it’s simple: you keep adding ammonia to the water – in small doses.

Initially, ammonia concentrations will spike (try not to exceed 2 to 4 ppm). Then, ammonia levels should start to gradually decline. As ammonia drops, nitrites will rise. And finally, as nitrites drop, nitrates will rise.

If ammonia levels are not dropping, then the nitrogen cycle isn’t happening. Do not add more ammonia, it won’t help. The issue most likely lies with the bacteria. In certain cases it just takes time, and you may need to give them a few extra days to “wake up” and do their work. If time doesn’t resolve the issue, you may want to consult with an expert as there may be other issues preventing the cycle from kicking off.

Once your tank is cycled, you are finally ready to buy your axolotl and introduce it to the habitat you’ve designed and built for it.

Regular Water Testing & Maintenance

You’ve probably already introduced your axolotl to its new home at this stage. It’s getting used to its new surroundings, and you and it are getting used to each other.

To keep your axolotl in good shape, you will need to do a couple of things on a regular basis:


Hello and welcome to Pets From Afar. I'm Glen. My daughter Siri and I are mad about axolotls. I created this website to document our findings and experiences, as we learn more about these amazing amphibians. Follow along and enjoy the fun!

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