Axolotl, an endangered paedomorphic salamander, is uniquely marked for its weird appearance.
Found in the lake complex of Xochimilco near Mexico City, they have some exclusive traits. This long-lived salamander-like species has a lot to unleash in front of us.
So, let’s know more.
The axolotl is a variety of salamanders that comes in a variety of pigments. They are native to freshwater lakes in Mexico. But they are now on their way to extinction due to various reasons. Nevertheless, these are easy to care for in a 20-gallon tank and best kept in cold water.
|Appearance||Smooth eel-like body with little limbs|
|Level of Care||Moderately easy|
|Life Expectancy||15-18 years|
|Tank Size||20 gallons|
|Tank Environment||Freshwater tank with a sand substrate and aquascaped with plants and other tank décors|
|Tank Mates||Better kept alone or petted with fish having similar requirements like Golden skiff, Zebra danio, Golden barb, Frail gourami, etc.|
Salamanders usually belong to the order Caudata, which is one of the three orders in the class of Amphibia. In Caudata, there are nine families with 60 genera and 600 species. Among these 9 species, one is Ambystomatidae, to which axolotls or Ambystoma Mexicanun belong.
There are at least more than 30 salamander species available who belong to this Ambystoma genus. They are mostly known as mole salamanders.
These are quite unusual among the other kinds of amphibians. They do not go through the process of metamorphosis when they reach adulthood.
They lack lungs like other salamanders. They possess gills. Rather than shifting to land, they prefer to thrive in the water for the rest of their life. Hence, do not get confused if you hear someone saying it a fish.
They are also known as “Mexican walking fish“.
Axolotl is a paedomorphic salamander closely related to the tiger salamander. With their small limbs, smiling faces, and fish-like appearance, they are a treat to watch.
These creatures tend to possess some extraordinary regenerative capabilities that make them a center of attraction for various studies and researches.
Name Origin: An Interesting Story
As the Aztec community moved to the valley of Mexico in the 13th century, they found several large salamanders thriving in the lake surrounding the island, where they had built their capital, Tenochtitlan. They named these salamanders “axolotl” after Xolotl, the god of lightning and fire.
As per mythology, Xolotl was transformed into a salamander to avoid getting sacrificed while letting the sun and moon move freely in the sky. Later he was captured and killed.
Aztecs captured and killed them for food. They are still used as food in Mexico.
However, they eventually became quite popular in the pet-keeping culture too.
Habitat and Ecology
Axolotls are native to freshwater lakes in the Valley of Mexico, namely Lake Chalco and Lake Xochimilco. In Lake Chalco, they no longer exist as it was drained by the 1970s to prevent flooding and expand urbanization.
Lake Xochimilco, the primary habitat, exists as a canal where the water temperature rises to 20° Celsius.
Axolotl In The Wild
Note: The dark-colored axolotls can shift their hue to various shades of light and dark colors as per necessity to camouflage with the background.
What makes them look so unique from other salamanders? Having a look at their appearance can make things easier for you to understand.
Their larval stage is quite similar to the appearance of tiger salamander species. It is pretty common to confuse them with mudpuppies due to the resemblance in appearance.
Stephen Jay Gould, the American evolutionary biologist, described these salamanders as “sexually mature tadpoles.”
Axolotls never really grow up; they retain their juvenile characters forever. This evolutionary phenomenon with “everlasting youth” is known as paedomorphosis or neoteny.
Neoteny evolution is the reason, they don’t lose their external gills while growing. And this is what separates them from other salamanders.
You can also find the presence of caudal fin in their body in the larval stage.
They have broad heads with lidless eyes. Moreover, their limbs look underdeveloped and come with long thin digits.
But are you wondering, where do the gills reside in an adult’s body? Their three pairs of external gills emerge from behind their head. They use it to get oxygen out of the water, just like any other fish.
Their external gill, also called rami, is nicely lined with fimbriae. It helps increase the surface area for exchanging gases underwater. Other four-gill slits are lined with gill rakers. They stay hidden underneath the external gills to prevent the entrance of food into the respiratory organ.
Males are pretty easy to identify with swollen cloacae lined along with their papillae.
On the other hand, females can be identified with their wide bodies filled with eggs.
Fun Fact: You can find vestigial teeth in axolotls that appeared during the period of metamorphosis.
Body color is another must-know fact about these species. They come in a unique variety of body pigmentation.
You will usually find four pigmentation genes in them. The normal wild-type axolotls feature a brown/ tan shade with a mix of golden and olive undertones. On the contrary, the other axolotl color morphs are pale pink, golden, grey, black, and pale pink with white and red eyes.
Size & Weight
A sexually mature adult will grow up to a length of 15-45 cm. It takes them to reach their maturity level at the age of 18-24 months.
They weigh around 50-300 grams.
Behavior & Temperament
They are solitary. So, you can see them remain active during any time of the day, even though they are primarily nocturnal.
Axolotls or A. mexicanum are most of the time passive. You can even get a smiling face vibe when you look at them, which is indeed very cute.
Don’t get carried away by looking at their cute little faces. They can become quite aggressive to each other if they get agitated due to any reason. Underfeeding or over-crowdedness in their surroundings can be a significant reason to get them cranky.
At times, axolotls even tend to snap at anything they get within their reach. Do not worry; they do not possess large-sized teeth that can harm you if they snap you while handling them.
You can call them much hardy in terms of their longevity. If they receive proper care and a suitable living atmosphere, they can thrive for 5-6 years.
Also, some species may live up to 10-15 years. Though there is a risk of dying after their metamorphosis, proper care and diet can make them live longer.
They prefer to communicate through their visual and chemical cues while they indulge in mating. Apart from the breeding season, they do not indulge in intraspecific communication during the year.
Fact: Axolotl can detect electrical fields and after recognizing it, they use their vision and chemical cues to get information about their environment and discover their prey.
The aquarium setup needs to be top-notch. Every tank component related to the care needs to be accurate. So, here is how you can set up an appropriate axolotl tank.
The aquarium where you keep your fish plays a crucial role in deciding the type of care you provide them.
A 10-gallon tank is not much suitable to make a fish sustain in the long run. But if you are thinking of starting small with a juvenile species, be prepared to adopt further changes in the long run.
It is usually recommended to opt for a larger tank as it serves enough space and surface for your cute little pet. For a single adult, a 20-gallon tank would be apt. If you want to keep more than one, simply add an extra 10 gallons for each.
To care for these salamanders properly in your tank, maintain stable and suitable water parameters. Here are a few water parameters that you need to consider while setting up an accurate tank for your pets.
It is always recommended to maintain a suitable water temperature that replicates their natural habitat. The optimum tank water temperature is 64° Fahrenheit. Though they might get sluggish due to colder water conditions, it won’t be much of an issue for them.
However, a high temperature can be a real issue in the tank. The temperature must not cross the mark of 75° Fahrenheit, as it can cause stress.
Perform a regular pH test to measure the acidity or alkalinity of the tank water. They can easily thrive in a relative pH range of 6.5-8. However, the suitable pH level is 7-7.5.
Water hardness is a big deal that you must maintain while keeping axol’s in your tank. The water hardness should generally lie within the range of 100-200 ppm.
Keeping the water clean in the tank is a real challenge. Especially while caring for sensitive salamander species like this, you must keep in mind that you are not exposing them to dirty water. Also, remember that they do not appreciate strong water flow.
You can add an air pump to run the filter in their tank. However, do not forget to check the noise level before choosing a filter for their tank.
Water Test Kit
Caring involves regular water testing to ensure consistency in the water parameters. So, if you are thinking of petting these, get a water test kit.
It is better to opt for a liquid test kit containing the necessary equipment to conduct NH3/NH4, NO3, and NO2.
Also, the kit must be able to monitor the water pH level.
Water heaters are not a vital component for the tank. They are coldwater species and do not need much heat. Hence, there is no need to opt for a robust water heating unit.
You can simply use a primary water heater to ensure that the tank does not face substantial temperature swings due to varied day and night temperatures. So, to maintain temperature stability, you can opt for a primary and moderately capable heater.
You need to take care of the lighting arrangement very precisely in the tank. Many hobbyists use strong lights to promote the optimal growth of plants, but this is not at all the right decision to make for this species. Instead, facilitate low to moderate lighting to take the best care of your tiny cute pets.
The substrate you are picking for the tank needs to be quite similar to their natural habitat. Axol’s are bottom dwellers. Thus, they spend most of their time near the bottom area of the tank.
Now, as they have sensitive skin, arranging a harsh or rough substrate might harm them. So, many keepers prefer to pick sand as the suitable substrate for this species’ tank.
You must remember one thing, i.e., they do not prefer bare places. Hence, there should be hiding places like cichlid rocks and ceramic pipes in the tank to rest appropriately and breed peacefully.
Also, you can incorporate driftwood and river rocks to hardscape the aquarium.
Aquarium plants should always be there in your considerations if you are setting up a tank. Go for some hardy plants, as this species tends to uproot delicate foliage. Plants like marimo moss balls are quite a suitable one for the tank. Also, plants like water wisteria, java fern, and anubias nana can work well with their tank.
Food & Diet
Diet plays a vital role in maintaining the excellent health. Thus, the food you are giving to them must be filled with necessary nutrients. They are predatory in the wild and simply eat whatever comes in their way.
Besides, they are also predatory by nature. Thus, their diet should contain a maximum amount of protein. In the wild, they usually feed on aquatic insects, small fish, worms, etc. But they also eat away other amphibians or their eggs and smaller axolotls.
Foods to Avoid
Before you delve deep into their diet, you must know what foods you should avoid giving them so that they can maintain a healthy food cycle.
Though they are a type of salamanders, they are not apex predators. Their stomachs can handle a lot of hard exoskeletons, they can cause impaction in them. Sometimes they might even get hurt by their prey.
You might find out in many books that axol’s can do fine with food like beef, heart, and liver; many hobbyists disapprove of it.
Also, it is better to avoid giving them feeder fish like goldfish that lack the necessary nutrients. Here are some foods that you should avoid.
- Hard exoskeletons of fish
- Beef liver and heart
- Wild-caught minnows
Before you start caring for axolotls in your tank, we suggest you know about suitable food. High-quality carnivorous foods work fine. Since their diet must include a rich source of protein, giving them animal-based food can be a good decision.
Worms are quite a good food option for them. Blood worms, daphnia can serve them a delicious treat with healthy nutrients. Food can also constitute blackworms, earthworms, pellets, etc. Besides, to maintain some variety in their diet, you can give them little guppies or minnows too.
Your duty is not only limited to feeding them. You must observe how much they are eating. It is always a better idea not to overfeed them. Also, underfeeding should be strictly avoided.
After you have fed them, remove any uneaten leftover food from the tank. They are much of a messy eater. They are very likely to miss the food, which is right in front of their eyes. But leaving uneaten food in the tank for a long time can cause damage to the water quality. Hence, you must clean it properly.
Care for this fish requires complete knowledge of its tank maintenance, water cycle, and water parameter requirements.
If you are new to the field of fish care or tank keeping, you can find axolotl care quite challenging. Thus, it is better not to jump into keeping them unless you have sound knowledge of handling them.
They are pretty easy to care for when you are aware of maintaining an optimum nitrogen cycle in the tank. They also need a continuous water supply to breathe, so it is better not to shift them often.
Besides, They come with delicate skin that has a coating of mucus layer on it. When you handle them, make sure you are not rubbing off this layer over their skin.
To move them to another aquarium, you can use a net to catch them and then transfer them with utmost care. Before adding them to a new tank, make sure to maintain a suitable temperature and water parameters in it.
Even though they have a unique regenerative power, they are quite susceptive to some common diseases.
Unsanitary tank conditions can lead to various bacterial or viral infections in them. In such cases, you can find the signs of lethargy or lack of appetite in your pets.
On the other hand, ammonia buildup in the tank can create toxic effects. It can harm their respiratory process by causing damage to their gills.
They are quite sensitive to any rough or sharp surface. Also, they have a very bad habit of gulping anything that comes in their way. Whether it is gravel or small stones, they will swallow anything that fits their mouth. This can lead to gastrointestinal problems.
In case you find that your axolotl is experiencing an obstruction and getting sluggish or refusing to eat, there are chances that they are suffering from some serious health issues.
They rarely undergo any metamorphosis in their terrestrial form. Thus, metamorphosis in them can be stressful or shorten their lifespan. But if any abnormal changes occur to the body, you must contact your vet at the earliest.
Breeding & Reproduction
Breeding is probably one of the most exciting things about this kind of salamander. You can notice courtship behavior in their breeding. This behavior is much similar to the general breeding pattern of Ambystoma.
The Mating Dance of Salamander Axolotl
Along with various unique and weird facts, the mating dance of these salamanders makes them quite an exclusive one as an animal.
Their reproduction starts with a happy dance. As the male and female nudge and stroke each other’s urogenital openings, they tend to form a circle in the form of a ‘waltz’.
The male struts away and keeps shimmying his tail like a hula dancer. Funny, right! But this action lures the female specimen to follow him.
As they step together, the male drops a tiny white capsule filled with sperm known as spermatophore. The female being in tow, the male moves ahead until the female borders the spermatophore and picks it up using her cloaca.
They go through this process of courtship once a year in the months from March to June. Followed by the courtship dance, the female releases 400-1000 jelly-coated eggs on the rocks or aquarium plants. Laying jelly-like eggs is one of the distinctive traits of salamanders.
It usually takes 10-14 days for the eggs to hatch. After the baby axolotls are born, it takes them 1 year to reach the level of sexual maturity.
However, you should keep one thing in mind axolotls have a 97% mortality rate in their larval stage. If they lay a minimum of 1000 eggs, you will only get 30 survivors from it.
Do you want to bring axolotls to take care of them in your home tank? If you are thinking of keeping them in separate tanks, there is nothing to worry about. But if you keep them in a community tank, then first know about suitable tank mates.
Since you already know that they are not much aggressive, keeping them with other aggressive fish species is not recommended. Some notorious fish species may tend to nip off their external gills, hurting them intensely. Choose tank mates for your axolotls very carefully.
Ideal tank mates are those who share similar behavior, tank requirements, and habitats. Also, this category should include faster fish so that it becomes hard for axolotls to turn their tank mates into delicious meals. Here are some ideal tank mates.
- Orange-finned danio
- Golden skiff
- Zebra danio
- White cloud mountain minnow
Potentially Good Ones
If you fail to get the ideal mates, you can simply go for the potentially good ones. However, keeping them with axolotls will need you to do a bit more research. Here, we suggest the names of a few potentially safer tank mates.
- Bengal danio
- Green swordtail
- Maharaja barb
- Mustached danio
- Dusky millions fish
- Frail gourami
- Golden barb
- Pearl danio
- Rainbow characodon
- Rosy barb
- Rosy danio
- Red-spotted panchax
Thus, while picking tank mates, make sure you test their compatibility. It is better to add those fish first and observe them. If you see any aggressive behavior, replace those fish immediately.
Also, make sure you are not introducing any infectious or sick fish to the tank to prevent disease outbreaks.
Frequently Asked Questions
Are axolotls endangered?
Yes, they are! IUCN listed them as critically endangered species. But then how many are left? Currently, only 35 species are found per sq. km. of Lake Xochimilco. Habitat loss and the introduction of invasive species are primary contributors to their extinction.
On the IUCN conservation index, these are marked as critically endangered species globally with their decrease in population of about 50-1000 adult specimens.
The surveys of 1998, 2003, and 2008 have discovered 6000, 1000, and 500 axolotls respectively present per square kilometer in their habitat of Lake Xochimilco.
Also, a four-month-long search in 2013 came across the fact that no surviving specimens existed in the wild.
However, just a month later, two wild axolotls were spotted in the network of canals connected to Lake Xochimilco.
A recent study carried out by a reckoned Mexican biologist, Luis Zambrano, found that there used to be around 6000 axolotls per square kilometer of their habitat in 1998.
Another recent survey from 2015 shows that there are only about 35 individuals left per square kilometer of lake Xochimilco.
Predators & Threats
Here are a few strong causes behind the quick extinction of axolotls in the wild.
- Water pollution: Due to the fast-paced urbanization of Mexico City, there is a rapid exposure of pollutants and chemicals to the lakes and canals of the Xochimilco network. Hence, the water has become inhospitable for aquatic life.
- Habitat loss: Due to the rapid development of Mexico City, vast areas of Xochimilco lake got drained and mostly destroyed. As a result, one of the most popular habitats, Lake Chalco, has also been destroyed, leading to a massive decrease in the number present in the wild.
- Overfishing: Overfishing has put them in significant danger. They have become a supreme delicacy in Mexico City. And this has led to a considerable increase in the demand in the fishery market. Hence, overfishing is another contributing factor to the extermination of this exotic species.
- Introduction of invasive species to their habitat: A handful of invasive species have been introduced to the habitat of axolotls. Bigger fish like carp, tilapia, and perch tend to eat away eggs and larvae, causing a potential threat to the existence of this salamander species in the wild.
- Sensitivity: These particular species are susceptible to harm and infections. Hence, any serious injury caused by other fish or bacterial or fungal infection can lead to their ultimate death. This is why they survive only 5-10 years in the wild. On the contrary, they can live up to 20 years in captivity subjected to proper care.
This fact is true to only the axolotls that belong to the wild arena. In captivity, there are plenty more than in the natural world.
Tens of thousands of these species can be found in home aquariums and research laboratories all over the world. But their population in the wild is in a sharp decline with a real threat to their lives.
Can axolotls go on land?
No, they can’t. This species has never been seen on the land.
Though, they can stay out of the water for a few seconds to 1-2 minutes. After that, they will collapse. Thus, while you opt for a water change, it is advisable to shift them to another tank filled with water to facilitate their easy breathing.
They feel comfortable enough to walk around at the bottom of the tank when there is sufficient water to support their gills and produce an adequate amount of oxygen for their well-being.
Is it legal to own a pet axolotl?
This is something that you must know before deciding to keep axolotls in your home. Keeping them as a pet is considered illegal in some states of America like New Jersey, California, Maine, and Virginia.
Usually, in New Mexico, they are legal to be your pet, but it is illegal to import them from other states.
These are usually native to Mexico and are known as endangered species due to the loss of their habitat. Thus, they must not be taken from the wild to the pet trade. The majority of pet ones are captive-bred animals that are used for scientific research.
Usage as a Model Organism and in Human Lives
Axolotls are very important as a research species. They are used in studies related to gene expression, neurobiology, embryology, and regeneration.
Researchers have found that they can perfectly regrow their new limbs 5 times. It takes only a few weeks in the wild to regenerate their injured or damaged limbs. Each tissue gets replaced with muscle, skin, bone, cartilage, and stem cells to give rise to newer limbs.
However, they can regrow the other organs innumerable times while making them completely functional. It is also said that they are more than 1000 times resistant to cancer than mammals.
Axolotls are pretty easy to breed compared to any other salamander species. Besides, as their embryos are large and easy-to-manipulate, they are used to study the full development of the vertebrate.
They are also predominantly used for studies related to heart defects as they have a mutant gene that causes heart failure in an embryo. However, their embryos can survive to hatch with no heart functionalities; hence, the defect is easy to observe.
Researchers consider it as an ideal animal for the study of neural tubes. It is so because it has similar traits to the human neural plate and tube formation.
It also takes part in studies related to mutations that can affect other organ systems. The genetics of different color variants is also a matter of never-ending research.
Besides, they are pretty popular in the commercial trade. They are in use for food purposes too. They have also been used for medicinal properties they possess. Thus, there is simply no negative effect on humans.
They are regarded as one of the top predators in their natural habitats. They simply eat anything they get access to. Thus, it enables them to maintain a healthy balance in the food cycle of our ecology.
In Popular Culture
The word axolotl has a foreign origin. Mad magazine adopted this term as nonsense to use it as running gags.
Also, in the fictional Dune universe of Frank Herbert, Tleilax used a technology named “axolotl tanks” for regrowing limbs.
In the Netflix series BoJack Horseman, you can find an anthropomorphic axolotl character, Yolanda Buenaventura. Natalie Morales voiced this character.
Besides, Julio Cortazar, an Argentine writer, included a short story named “Axolotl” in his collection of Final del Juego. This story centers around a man who becomes obsessed with salamanders as he views them in an aquarium in Paris.
In 2020, an announcement was made that axolotl will be featured on a new design of 50-peso banknote of Mexico. It would also include the images of chinampas and maize. The banknotes are about to get circulated by 2022.
At Minecraft Live 2020, Mojang Studio announced that axolotls would get added to the sandbox game Minecraft in its 1.17 update. It was supposed to be released in 2021. This innovative idea is intended to increase awareness of the risk of this to-be-extinct animal.
Axolotl species that belong to a group of salamanders deserve a special mention among amphibians. Whether it is their cute little limbs with a fish-like body or their unique way of regenerating limbs, everything makes them quite interesting.
Don’t you think their way of remaining as an aquatic animal even after metamorphosis makes them stand apart from other popular amphibians? Learning about them can naturally make you more interested in keeping them in your home tank.
So, if you are thinking of caring for them in your home tank, make sure to have first-hand experience in fish keeping. Maintaining a top-notch aquarium setup and tank mates are crucial for better care.