Known as the Salamander that never grows up, Axolotls are just so gosh darn cute!
So you’ll want to provide them with an outstanding, but easy-to-maintain environment so you can keep your little one smiling!
In this article, you’ll learn exactly that. But it’s a bit long, because I wanted to bring you the best care sheet possible. So be sure to use the buttons in the table of contents to help navigate the article to information you need.
Table of Contents
- In the Wild: What is an Axolotl, is it the same as a Mexican Walking Fish?
- Main Axolotl Morphs
- Part 1: Setting Up Your Axolotl’s Habitat
- Part 2: Getting your Water Conditions Right
- Part 3: In-Tank Behaviour and Tank Mates
- Part 4: Dietary Requirements
- Part 5: Understanding Axolotls’ Genetics, Biology, and Breeding
- Part 6: Illness, Disease, Injury, and Treatment
- More FAQ’s
In the Wild: What is an Axolotl, is it the same as a Mexican Walking Fish?
Commonly referred to as the Mexican salamander, or Mexican “walking fish”, an axolotl has an appearance unlike any other aquatic animal.
Here’s the deal:
Even though it’s normally categorized as a fish, an axolotl is actually not a fish at all. It’s a species of amphibian (technically it’s part of the salamander family).
But here’s the real kicker:
Unlike most amphibians, adults remain aquatic even after developing legs.
Axolotls can grow anywhere between 15-45 cm long (but most usually grow to be about 30 cm).
He’s quite a looker, too- ol’ axolotl, with his wide head, lidless eyes, and four long, thin legs.
As if that wasn’t enough to get any amphibian’s heart thumping, axolotls also have filament-lined gill stalks (which are called rami) that stick out from the back of their necks.
Sadly, the world’s only remaining population lives in Lake Xochimilco.
Because of their scarcity, axolotls are listed on the International Union for Conservation of Nature’s annual Red List of threatened species.
Hold up, how did that happen?
Well, the population took a massive hit when Lake Calcho (axolotl’s native Mexican habitat) was drained to avoid flooding.
As a result, huge numbers of axolotls were killed while the remainder began populating the canals of Xochimilco.
Main Axolotl Morphs
Axolotls come in many different colors:
Wild-Type: Mottled green with bright eyes purple gills.
Albino: White/pale pink with clear/pink eyes and red gills.
Melanoid: Black/dark grey with black eyes and dark gills.
Leucistic: White/pink with dark eyes and bright red gills.
Golden Albino: Golden with pink/orange eyes, bright red/pink gills.
Copper: Copper with dark eyes, bright red/pink gills.
GFP: Sometimes, a recessive gene called Green Fluorescent Protein (GFP) may be present, causing axolotls to glow green under black lighting.
Other variations: Other, less common morphs may include Piebald, Golden Non Albino, and Chimaerism.
Part 1: Setting Up Your Axolotl’s Habitat
Axolotls are accustomed to the waters of Mexican lakes, meaning they have quite a few special needs you’ll need to consider when setting up their habitat.
What’s The Best Aquarium Size?
Axolotls can grow quite large, so they need a lot of room to live happily and healthily.
An individual axolotl should have no less than 10 gallons of water in its habitat.
Yup, you read that right. Ten. And bigger is always better!
And just to be clear:
Two axolotls would require 20 gallons, three would need 30, and so on and so forth (you get the drift).
You should never house young axolotls (>8 cm in length) together in confined spaces. They’re known to nip at each others’ gills, which can sometimes end up with them inflicting pretty serious damage to their tank mates.
Giving your pets plenty of room to move around without getting in each other’s way will reduce the risk of them harming one another.
What kind of Substrate Should I use?
Poor quality or inappropriate substrates can be very damaging to axolotls (think serious injury or even death).
Because axolotls feed by sucking water into their mouths.
“Okay…” I hear you say, “…so what?”:
Well, this basically means that your axolotl could accidentally ingest particles from your substrate (like gravel, for example). And if that happens, we’re talking about some serious gut problems, like impaction.
It’s therefore crucial the substrate you choose is suitable for your pet.
Here’s an expert tip:
Substrates aren’t always essential when keeping an axolotl. Often, the bottom of your tank can be left bare, which means totally avoiding the above problem.
A bare-bottom tank can sometimes cause axolotls distress if they’re unable to grip the tank’s surface and walk properly.
So, what’s the takeaway?
Using an appropriate substrate is your best option.
Sand is the safest choice; particles of sand are very small and won’t cause any serious problems if your axolotl ingests them.
Another big plus:
Axolotls love to dig and play around in the sand, which can massively boost their wellbeing and help ensure that they don’t become distressed.
To top it all off, plants, hiding spots, and decorations are also very easy to add in when you’re using a sand substrate.
What kind of Filtration will I Need?
Axolotls are particularly sensitive to poor water conditions (like, really sensitive).
Experts recommend a weekly water change of at least 20% and a high-quality filtration system.
Axolotls are adapted to survive in still waters, which means it’s insanely important that the filter you choose doesn’t disturb your tank’s water flow.
Whatever you do, don’t mess with the flow, man!
External canister filters fitted with flow-spreading outlets (like a spray bar) will keep your water clean without upsetting its flow.
If you find that your filter is too powerful, try putting in a couple of plants. They can help to block excess movement and soften strong currents.
What kind of Lighting is Best?
Axolotls are used to the low-lighting conditions found in their native Mexican habitats.
And like the majority of amphibians, axolotls don’t need any special lighting- phew!
Bright lights can actually be quite distressing to them since they don’t have eyelids.
Even so, a lot of aquatic hobbyists still choose to install decorative lights to enhance their own viewing pleasure.
What will happen if you do?
Well, it could cause some initial distress, but axolotls will be able to get used to artificial lighting over time. Adding decorations and hiding spots to your tank will help ease this process.
If this distress continues, you should adjust the lighting in order to prevent any stress-induced illnesses from forming.
Should I be Adding Plants and Decorations?
Since they spend most of their time along the bottoms of waters, axolotls love to hide and forage amongst silk and live plants such as java mosses, anubias and hornworts.
You know what else they love?
Caves. Who doesn’t like a good cave?
Caves serve as great hiding spots. Shop-bought cave decorations, PVC tubing and plant pots all work well when it comes to giving axolotls some comforting places to hide.
Part 2: Getting your Water Conditions Right
Maintaining the correct water conditions is vital to your axolotls’ health, wellbeing and longevity.
Pro Tip: Whenever you start a new tank, you’ll need to go through the process of cycling your aquarium before adding animals. If you’re unsure, check out our easy, step-by-step Nitrogen Cycle here.
How to Provide the Correct Temperature and Cooling
Getting the right temperature in your aquarium is crucial if you want to ensure that your axolotls stay healthy- which obviously you do!
Their tank needs to be kept at a stable temperature of 15-23 degrees Celsius. Your tank’s temperature shouldn’t exceed 24 degrees Celsius. Ever.
If it gets too hot, your axolotls could become very distressed, which can cause reactions like fungal infections, loss of appetite, and even death.
On top of that:
High water temperatures can also increase the toxicity of ammonia in your water, which is seriously harmful to axolotls.
If they’re too cold, your axolotl’s metabolism will begin to slow down, which will make it sluggish and unwell.
That’s why it’s crucial to your axolotl’s health and wellbeing that you keep temperatures within the appropriate range.
If you can’t maintain lower temperatures year-round, aquarium chillers can help to cool your waters.
How to get your Water Flow Right
Axolotls are accustomed to stable water conditions.
Unlike most fish, axolotls don’t tolerate distinct water flow. If they’re exposed to it, they’ll quickly lose their appetite and potentially develop stress-related illnesses.
Filtration systems can sometimes disturb water flow. Flow-spreading outlets like spray bars can minimize this.
Lack of appetite or forward-turned gills on your axolotl are both stress-related signs that the aquarium’s water flow is too high and should be changed.
Getting your pH: Acidity & Basicity/Alkalinity Levels Correct
Though a pH of 6.5-8.0 is acceptable for axolotls, you should aim for a pH of 7.40-7.60 to keep them healthy.
And keep it stable. A stable pH is vital.
But, why is pH so important?
It can affect the toxicity of ammonia in your water, which can potentially give rise to ammonia poisoning- yikes!
If your water is particularly acidic or basic, you can adjust its pH using salts and pH-changing kits (which most aquatic retailers sell).
A Word on Chlorine and Chloramines
Chlorine is a highly-toxic green gas that can seriously harm amphibians, fish, and humans.
Yuck, why does something like that even exist?!
Well, it’s commonly used to kill bacteria in municipal water supplies before the water is distributed for public use.
You know what else is toxic?
And when you combine it with chlorine, it can form products called chloramines.
It’s therefore essential to use a dechlorinator whenever you add water to your aquarium.
Dechlorinators remove chlorine, chloramines and many other trace metals (such as mercury and lead) from water, which makes it safe for your axolotl.
You should always use a dechlorinator when changing water. If you’re unsure whether these harmful substances have been successfully removed, chlorine testing kits can measure their quantities.
Understanding Ammonia, Nitrite, and Nitrate
Ammonia is a waste product produced by axolotls and many other aquatic animals.
Ammonia is very toxic in its unionized form.
High pH levels keep ammonia in this form, and at a pH of 8 or more, ammonia can kill axolotls very quickly.
Water temperature can also increase the toxicity of ammonia.
You should definitely conduct routine ammonia tests (which are easy to buy from most aquatic retailers) on your water to ensure that it’s safe.
Nitrite is a product of ammonia and, though it is less toxic than ammonia, you should always test for it with an appropriate test kit.
Less toxic still, nitrate is formed from nitrite.
Although not toxic at low levels, nitrate can become dangerous if you let it build up, which might lead to algae blooms.
Regular water changes will keep nitrate contents in check, though it’s wise to test your water’s nitrate contents periodically.
You can find more information in our Nitrogen Cycle Guide.
Water Hardness and Dissolved Salts
Water hardness is the term we use to describe the amount of dissolved salts in a particular body of water.
People that live in “hard water areas” regularly find their pipes and kettles lined with limescale. This limescale is actually calcium and magnesium salt deposition (phew- there’s a mouthful!).
Soft water areas will not have this same issue.
These salts can affect the chemical balance in an aquarium.
Soft water often increases water acidity, while hard water tends to make water more basic/alkaline.
Here’s the most important part:
Axolotls are best adapted to hard water conditions.
Soft water may give rise to temporary anemia which you can recognize if you see pale pigmentation and gill discoloration.
Though temporary anemia isn’t harmful, it is a sign that your tank’s conditions are less than ideal.
You can prevent this by adding salts to increase the hardness of your water.
Indiana University’s Axolotl Colony uses an altered Holtfreter’s solution – a combination of NaCl, KCl, CaCl2 and MgSO4 salts.
Such a solution will work well to maintain a suitable water hardness for your axolotls.
Part 3: In-Tank Behaviour and Tank Mates
As a rule of thumb:
It’s not smart to house axolotls alongside any other fish or salamanders.
You and I both know that axolotls are good lookin’ amphibians (am I right?!)…
You know who else thinks so?
Which is probably why they like to nibble away on axolotl gills whenever they get the chance! Cheeky buggers.
Salamanders and newts are also common culprits, especially during feeding times.
Logically, you might think that larger axolotls wouldn’t face this issue; smaller fish wouldn’t dare attack a salamander that much bigger than they are… right?
It’s true, but:
Housing axolotls with smaller fish will most likely lead to their demise.
Axolotls are known to eat pretty much anything that fits in their mouths (I know some humans like that, too) including small fish, shrimp, and even other axolotls- jeez!
So what can we take from this?
Axolotls should not be kept in a tank with other aquatic species.
Younger axolotls (around 8-16 cm in size) shouldn’t be housed together for this same reason: they’ll nip each other’s gills and feet and could cause serious damage.
Wild-type axolotls are particularly notorious for this nasty habit.
Fully-grown adult axolotls, on the other hand, may live together safely and will rarely attack one another.
Part 4: Dietary Requirements
Axolotls are carnivorous. Their diet is purely meat-based and is made up of several species of animals found in Mexican lake waters.
What do Axolotls Eat?
In the wild, axolotls are known to eat worms, insects, small fish, and anything they can fit into their mouths and swallow whole – even other salamanders.
But in an aquarium:
Organic nightcrawlers (large earthworms) are the most nutritional food source for axolotls. Blackworms and bloodworms are also healthy choices.
As a treat, axolotls enjoy eating frozen shrimp, prawns, mealworms, tuna and lean chicken or beef.
Like most salamanders, axolotls don’t need any vitamin/mineral supplementation.
How Often Should Axolotls be Fed?
In a nutshell:
Axolotls will eat until they are full.
Adult axolotls tend to eat around two earthworms every 2-3 days, and it’s pretty normal for them to pass up on food if they’re still full from previous feeding sessions.
On the other hand:
Growing axolotls will feed daily.
Once you get to know your pet, you’ll quickly learn how and what it likes to eat.
How Long Can They Go Without Food?
A healthy adult axolotl can live healthily for up to two weeks without food- pretty crazy right?
You should feed younger, growing breeds more regularly and, ideally, you shouldn’t leave them longer than three days without feeding them.
Part 5: Understanding Axolotls’ Genetics, Biology, and Breeding
Before getting to the facts about how to breed axolotls, we first need to go over a few key points about their genetics and biology.
Understanding The Biology of Your Axolotl
Unlike other amphibians, the axolotl retains its larval form into adulthood. This adaptation is referred to as neoteny. It reaches sexual maturity in this state.
The axolotl’s internal biology represents its carnivorous nature.
What do we mean by that?
It has small, stump-like teeth that grip food before it’s swallowed whole.
Axolotls also have rudimentary lungs that require it to rise to water surfaces occasionally to take in air. These lungs tend to develop shortly after their legs reach full length.
Let’s start at the start:
Axolotls grow from eggs. These eggs are comprised of an embryo and layers of jelly (which is made up of water and a substance secreted when eggs are laid).
At about 11mm, the embryo hatches and a young, limbless larva emerges.
Larval axolotls are transparent for their first few weeks of life, and their organs and digestive progress is visible until their skin thickens.
After around two weeks, their front legs develop; hind legs follow a few weeks afterward. At this stage, axolotls become what we like to call ‘miniature adults’.
Adults will reach their full size after around 18 months to 2 years depending on their rate of feeding and aquatic conditions.
Sexing and Reaching Sexual Maturity
You can distinguish between male and female axolotls by looking for two characteristic features:
Males tend to have a swollen cloacal (lower abdominal) region, while females have thinner cloacal regions and more rounded bodies for egg storage.
Mature males tend to appear more elongated and have longer tails.
Golden, white and albino axolotls that are sexually mature often have dark brown toe-tips and darkened soles. Wild-types and melanoids also exhibit discoloration, though their toe tips tend to lighten rather than darken.
You should also note that males don’t always have sperm readily available for mating.
It takes males around 2-3 months to produce sperm and a further 2 months for them to position the sperm for ejaculation.
Make your plans for breeding around this cycle.
Understanding the Genetics
While humans have 46 chromosomes in each bodily cell, axolotls have only 28.
In case you didn’t know:
Chromosomes are long coils of DNA that tell cells how to function. Without DNA, no organism could survive- so these chromosomes are pretty important, to say the least.
Let’s get down to the birds and the bees:
During axolotl reproduction, male sperm cells combine with female egg cells, each with 14 chromosomes, to create a cell with a total of 28 chromosomes called a zygote.
This zygote contains genetic data from both maternal and paternal DNA.
For this reason, offspring inherit characteristics from each parent.
Understanding Alleles Made Easy (I hope, I promise I did my best)
Male and female sex cells (called gametes) contain variations of genes called alleles.
Think of them like codes:
These alleles code for various characteristics like eye color and skin pigmentation.
Alleles can be either dominant or recessive. It’s the combination of these alleles that determine how an organism develops.
An axolotl’s DNA may contain the alleles A and a, where A is a dominant allele (in this example a wild-type morphism) and a is a recessive allele causing albinism.
If the alleles A and A combined, a wild-type axolotl will form. A/a would also cause this, as the A allele (coding for a wild-type axolotl) is dominant.
Still with me?
Okay, just a little bit more to go:
If a/a were combined (i.e. two recessive alleles) only then would the result be albinism. No other combination would cause this, as a is a recessive allele, overridden by dominant alleles.
Such combinations may occur depending on the alleles present in male and female gametes.
A female carrier of an a allele, bred with a male carrier of the same allele, would certainly create an albino offspring.
In this way, you can pretty much guess the phenotype (physical appearance) of future offspring before breeding.
Axolotls are fairly easy to breed, but there are still some measures you should take to ensure they’re able to mate successfully.
Axolotls can reach sexual maturity anywhere between 5 months and a few years.
You shouldn’t attempt to breed axolotls before the age of 18 months.
You want to first give them time to reach full size.
Female axolotls can produce more than 1,000 eggs- which is pretty impressive! The body prioritizes egg production over other processes like growth.
But you should be aware:
This can be incredibly taxing and damaging to a non-developed axolotl, which is why breeding before 18 months isn’t a good idea.
It’s possible to breed axolotls at any time of year, though some sources advise that breeding is most successful from December to June.
Here’s what the studies say:
The University Of Indiana Axolotl Colony subjected males and females to decreasing periods of daylight to trigger spawning. The results were pretty effective.
You can try to replicate these conditions, but before you go to all that effort you should keep in mind that any room in your house that’s exposed to seasonal changes (even partial ones) usually provides good enough conditions to spur on breeding.
A pair of axolotls in perfect conditions with natural light should breed around once a year. But do be prepared for the fact that they’re notorious for reproducing at odd, unpredictable times.
Setting Up Your Breeding Tank
You should populate your tank with many silk/live plants to give females a place to affix their eggs.
Rough pieces of stone/slate should also be placed along the bottom of your tank, which will give males a place to deposit spermatophores.
Courtship and Spawning
Males initiate spawning.
Here’s the down and dirty:
They deposit around 5-25 spermatophores on top of stones and other items around their habitat.
During a typical breeding session, male axolotls will raise their tails, making vigorous writhing motions at the female as he leads her around the tank to their previously deposited spermatophores.
Pro Tip: Don’t try this at home, I can attest this is far less effective on human females.
She’ll then pick these up and fertilization will take place internally.
Between a couple of hours and two days later, she’ll lay her eggs individually atop plant leaves, rocks, and scattered randomly around the tank.
She might lay 100-1,000 eggs per spawning session.
Hatching the Eggs
While albino morph eggs will appear bright white after a few hours, normal eggs will be dark brown.
After 2-3 weeks, these eggs will hatch and axolotl larvae will emerge.
Keep the eggs kept well-aerated; an air pump will help to do this. At 20 degrees Celsius, eggs should hatch around 14-17 days later.
Part 6: Illness, Disease, Injury, and Treatment
There are a number of illnesses and injuries that axolotls can sustain. It’s vital that you learn how to treat these effectively so that you can bring your pet back to health quickly.
Stress is one of the biggest causes of illness in axolotls. Chronic stress can lead to illness or infection.
Common Causes of Stress
- Strong water flow
- Temperatures over 24 degrees Celsius.
- Untreated water
- Foul water
- Aggressive Tank mates
Common Signs of Stress
Stressed axolotls often lose their appetite, refusing to eat normally.
On top of that:
Signs like curling/hooking of the tail and forward-turning gills are signs that your pet is suffering from stress.
Axolotls have a fascinating ability to regenerate lost limbs without any help whatsoever.
With enough time, axolotls that have sustained injuries (such as damaged gills or limbs) will repair themselves fully.
The only risk with injury is infection.
Exposed wounds can quickly become infected, so you should always keep wounded axolotls in cool, clean water.
Impaction is a condition found in axolotls when the digestive system becomes dysfunctional.
Symptoms of impaction include:
- Refusal to eat for multiple days
- Low waste production
Often, this is caused when they ingest gravel or small stones, which is why it’s crucial that you house your axolotl with an appropriate sand-based substrate.
In the case of impaction, fridging can encourage fast recovery and help them to eject anything nasty in their digestive system.
Constipation as a result of overfeeding can also cause impaction, which is why adults should only be fed every 2-3 days at most.
Axolotls are able to float around tanks at will, though excessive floating may indicate air bubbles in the gut.
This should only become a concern if:
- Your axolotl is unable to return to the bottom of the tank
- They float up against their will
- They float very often
- They appear distressed when floating
Again, fridging can help get rid of this problem. You should also check your water parameters and adjust them if necessary.
Heat-stressed axolotls can develop dangerous bacterial and fungal infections, which is why you should routinely check your water temperature.
Common illnesses include ‘red leg’ bacteria, characterized by red patches on the limbs; Columnaris, characterized by sluggishness and white grey patches; and Saprolegnia, characterized by white patches on skin and gills.
These can all be treated using a salt bath or fridging.
Axolotls are native to cold water. For that reason, you can use lower temperatures to slow disease and infection.
It’s also beneficial for impaction:
In cool temperatures, undigested food is ejected to prevent rotting.
To fridge an axolotl:
1. Make sure your fridge is between 5-8 degrees Celsius
2. Prepare a container of dechlorinated water (not chilled) long enough for your axolotl to stretch to its full length. The container should have a lid with air holes and space at the top for the axolotl to jump up for air.
3. Transfer the diseased axolotl to the container and cover with a towel to prevent light disturbance.
4. Once in the fridge, change water daily, replacing old water with dechlorinated, refrigerated water.
5. Keep the axolotl refrigerated until it recovers.
6. Gradually re-introduce your axolotl to tank water before returning it.
Axolotl Salt Bath
You can use salt baths to treat axolotls suffering from skin infections, which is most effective when used in conjunction with fridging.
Axolotls with fungal infections will benefit from salt bathing. The salt works to kill off any infection, nursing axolotls back to health within a few days.
Salt baths should be given twice daily during infection, for 10 minutes at a time.
– Mix 1-2 liters of dechlorinated water with sea, rock, or aquarium salt. Avoid table salt.
– Refrigerate to the same temperature the water you’re using for fridging.
– Remove container from refrigerator once cooled and shake.
– Fill your salt bathtub and add your axolotl.
– Leave for 10-15 minutes maximum.
Remove from the tub and return to the fridging container.
– Repeat every 12 hours until the infection clears, and for 2-3 days after to kill any remaining fungus.
Here’s are a few more commonly asked questions for you:
How is axolotl pronounced?
What’s the scientific name?
How big do they grow?
How long do they live for?
Up to 15 years, approximately 10 years on average.
How can you tell if an axolotl is male or female?
Males are longer, with a swollen cloacal region. Females have larger, rounder bodies for egg storage.
How do axolotls reproduce?
Males leave spermatophores around the tank which it leads the female towards during breeding. These fertilize female eggs.