Axolotls make for unique and intriguing pets, but providing the proper housing for these aquatic salamanders is key to keeping them healthy and happy. If you’re considering getting an axolotl, one of the first decisions you’ll have to make is what kind of tank to house them in.

If you’re short on time, here’s a quick answer: a long, low tank that holds at least 20 gallons and has plenty of floor space is best for axolotls. They need room to move around and should not be kept in tall, narrow tanks.

In this comprehensive guide, we’ll cover everything you need to know to choose the perfect axolotl tank, including key factors like size, shape, substrate, filtration and more. Read on to learn how to create the ideal aquatic environment for these fascinating creatures!

Tank Size Requirements

Minimum Tank Size

The absolute minimum tank size for one axolotl is a 20 gallon long tank. This provides enough room for your axolotl to move around comfortably. However, a 20 gallon tank is really best for axolotl juveniles or small adults under 5 inches long.

For full grown adults, a minimum of a 29 gallon tank is recommended.

Keeping an axolotl in too small of a tank can cause stress, inhibit growth, and lead to health issues. Axolotls have a large bioload and require frequent water changes in small tanks to keep the water clean. It’s best to provide the largest tank possible to give your axolotl room to thrive.

Ideal Tank Size

While 20-29 gallon tanks meet the minimum requirements, most axolotl experts recommend a larger tank if possible. A 30-40 gallon breeder tank is ideal for one adult axolotl. This gives them enough room to fully stretch out and walk around.

For two axolotls, a 40 breeder or 55-75 gallon tank is recommended. Never keep more than two axolotls in the same tank, as overcrowding causes stress and aggression.

Bigger is always better when it comes to axolotl tanks! A large tank dilutes waste and requires less frequent water changes. It also provides enrichment through more space to explore and exercise.

Floor Space Considerations

Floor space is more important than total tank volume for axolotls. They utilize the bottom of the tank much more than open water column space.

  • A 20 gallon long (30″ x 12″) provides more usable floor space than a 20 gallon high (24″ x 12″).
  • Look at the tank’s footprint rather than just total gallons. Prioritize floor space over tank height.

An adult axolotl should have at least 2 square feet of floor space as a minimum. But the more the better!

Tank Shape and Dimensions

Rectangular Tanks

When choosing a tank for axolotls, a rectangular shape is ideal. Rectangular tanks provide more floor space, allowing axolotls to move and turn around comfortably. A good rule of thumb is to select a tank that is at least 2-3 times the length of your fully grown axolotl.

For most axolotls, a tank size of 20 gallons or larger is recommended.

The extra floor space of a rectangular tank is especially important as axolotls grow. Axolotls can reach up to 9-12 inches in length when fully grown. Trying to fit an adult axolotl in a small, cramped tank would be quite problematic.

Axolotls are active swimmers that need room to roam and explore their habitat.

Some specific recommendations for minimum tank sizes are:

  • 1 Axolotl: 20 gallon long tank
  • 2 Axolotls: 29 gallon long tank
  • 3 Axolotls: 40 gallon breeder tank

Standard 20 gallon long tanks provide an excellent starting point for juvenile axolotls. For multiple adults, aim for at least a 40 gallon breeder which offers increased floor space. The extra room allows axolotls to establish their own territories and reduce stress.

Avoid Narrow, Tall Tanks

While a rectangular tank maximizes useful space for axolotls, an overly tall and narrow tank is less than ideal. For example, a 20 gallon high tank may hold the same volume of water as a 20 gallon long, but provides far less floor space.

Narrow tanks dramatically limit horizontal swimming area. Axolotls often end up bumping into the glass sides frequently as they try to turn and maneuver. Lack of floor space can stress axolotls out and cause accidental injury.

Make sure to avoid buying hexagon tanks or round fish bowls. These unconventional shapes look interesting, but provide even less usable floor space than a tall rectangular tank.

Stick with traditional rectangular tanks for axolotls. Prioritize length over height to give your aquatic salamander the room they need. Carefully research tank dimensions before purchasing.

Choosing the Right Substrate

Bare-Bottom Tanks

Bare-bottom tanks are exactly what they sound like – aquariums with no substrate at the bottom. The glass bottom of the tank is left completely exposed. This option has advantages and disadvantages for axolotl owners.

On the plus side, bare-bottom tanks are very easy to keep clean. With no sand or gravel, there are no particles that need siphoning. Owners can simply use a scrubber on the glass periodically. There are also no concerns about axolotls accidentally ingesting substrate, which can cause impaction.

However, bare-bottom tanks completely lack enrichment. Axolotls love to dig and sift through substrate. Depriving them of this opportunity leads to boredom and stress. The lack of plants is also detrimental. Most aquatic plants require a substrate to root in.

Without plants, water parameters can easily crash.

Fine Sand

Fine sand is the most commonly recommended substrate for axolotl tanks. A fine grain size between 0.5-1mm is ideal. This sand is small enough to pass through axolotls’ digestive systems safely when accidentally ingested.

Popular options include Caribsea Super Naturals and Poly-Fil sands. Pool filter sand also works well. With sand, axolotls can exhibit natural behaviors like digging and burrowing to their heart’s content.

Sand also allows for live plants in the tank. Plants like anubias and java fern thrive when their roots can anchor in a soft substrate. Aquatic plants help improve water quality and oxygenation.

When using sand, axolotl owners should siphon the tank regularly with a gravel vacuum. This removes trapped debris and prevents toxic gas pockets from accumulating in the substrate.

Smooth Gravel

Smooth gravel between 3-5mm diameter can also work as an axolotl substrate. But it does carry higher impaction risks than fine sands. Owners must carefully monitor their axolotls and remove any larger pieces that can be swallowed.

Gravel allows efficient waste removal since debris settles on top instead of getting trapped between grains. But axolotls may have a harder time digging and burrowing comfortably. Smooth and rounded gravel is essential to prevent injury to axolotls’ sensitive bellies.

Small plant bulbs can be grown in gravel successfully. However, plants with extensive root systems will not thrive. Gravel tends to compact over time too, which further limits plant growth.

With vigilance and routine maintenance, gravel can make an acceptable axolotl substrate. But smooth fine sand is generally the safer recommendation for pet axolotl tanks.

Filtration System

A proper filtration system is crucial for keeping axolotl tanks clean and healthy. The two most popular options are sponge filters and canister filters. The ideal filtration system provides gentle water circulation without too much flow to stress delicate axolotls.

Sponge Filters

Sponge filters are a top choice for axolotl tanks. These simple, affordable filters draw water through a sponge, allowing beneficial bacteria to grow and convert toxic ammonia into less harmful nitrate.

Sponge filters offer gentle water flow perfect for axolotls. They also provide surfaces for helpful bacteria to colonize. Many axolotl keepers use air-powered sponge filters combined with air stones to lightly agitate the water.

Popular brands like XY-2831 and Jardin In-Tank are affordable but effective options.

Canister Filters

Canister filters like Fluval or Eheim are more powerful external filtration systems. They offer larger media baskets to house filter materials like ceramic rings, activated carbon, and bio balls that trap debris and house nitrifying bacteria.

The main downside of canister filters for axolotls is their stronger flow rate, which can stress sensitive axolotls. However, flow can be diffused by pointing the output nozzle up to break up the current or adding pre-filter sponges.

Water Flow Rate

Axolotls come from nearly still lake bottoms, so filtration should provide gentle circulation. The ideal flow rate is just enough surface agitation to circulate water through filter media for waste breakdown.

Water churning from strong currents can stress axolotls. Signs include clamped fins, swimming issues fighting the flow, or gulping air at the surface. Axolotls may even bite their own fans if stressed by high flow.

As a general guideline, water flow should turnover the tank volume 5-10 times per hour. So for a 20 gallon tank, optimal circulation is 100-200 gallons per hour. Breaking the flow by pointing spray bars or nozzles upward helps prevent axolotls from being swept around.

Adding spray bar attachments, gang valves, or flow diffusers are easy ways to adjust canister filter outputs. Positioning plants, tank decorations, and other breaks in open areas also lets axolotls rest from any currents.

Additional Tank Needs


Proper lighting is crucial for axolotls. Since axolotls originate from underground caves in Mexico, their eyes are accustomed to low light conditions. Too much light can stress them out. The best option is to use a low wattage fluorescent or LED aquarium light for 10-12 hours per day.

This provides enough light for live plants without being too harsh on axolotl eyes. Some owners also use blue or red LED strip lighting which offers an attractive shimmering effect. Avoid bright white light or direct sunlight which can damage axolotl eyes and skin over time.

Hiding Spots

In the wild, axolotls spend most of their time hiding in rocks, plants and little crevices. Thus it is important to provide plenty of hiding spots in the tank. Good options include:

  • Ceramic pipes/tunnels
  • Terracotta pots laid on their side
  • Plastic tubes or PVC pipe sections
  • Store-bought caves and shelters
  • Live or artificial plants

Aim to offer at least one hiding place per axolotl. Position them throughout the tank to provide a feeling of security and to allow each axolotl some personal space if needed. The hides also help reduce stress when axolotls need to get away from light or tank maintenance activities.

Plants and Decor

Plants and tank decorations serve both a practical and aesthetic purpose. On the practical side, they provide enrichment by offering extra hiding spots and surfaces to explore. Smooth rocks, driftwood and aquarium-safe plastic plants are good basic options.

Live plants like anubias, java fern and amazon sword add natural beauty while also filtering the water. Just be sure any decorations have smooth edges and cannot easily fall over and injure your pet.

When it comes to substrate, bare bottom is easiest to keep clean but lacks visual appeal. Sand offers a nice natural look but requires more maintenance to prevent debris buildup. An appealing compromise is to use large smooth river rocks or a mix of larger gravel and smooth pebbles.

This allows waste to fall through while still being visually interesting.

Themed decor can also make your axolotl tank into a unique underwater showcase. Go for a natural look with driftwood, live plants and a forest floor substrate. Or create an ancient ruins or pirate shipwreck scene with plastic corals, chests and skeletons.

Just be sure any decorations are aquarium-safe and provide ample room for your axolotls to comfortably move around.


Providing an appropriate tank for axolotls takes some special consideration, but it’s manageable with the right information.

Focus on giving them plenty of floor space, using safe substrates, installing low-flow filtration, and adding enrichment items to keep them active and comfortable. With an adequately sized and well-furnished habitat, your axolotl will thrive under your care!

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