What do Axolotls Eat? - Feeding and Fun Facts

Although it may look like a tadpole which never properly grew up, the axolotl (Ambystoma mexicanum) is a curious species of amphibian in its own right. They are neotenic, meaning they have physical characteristics of younger individuals in their species although they may be in the adult stage. Endemic to the Valley of Mexico basin, they have been in critical danger of extinction since at least 2006.

Lake Xochimilco in Mexico City is an ancient lake which has been very important to the indigenous population of Mexico. More recently it has become a large recreational space and tourist attraction where colorful boats wade up and down with festivities happening on-board. Unfortunately for the axolotl, this has helped to severely decrease their wild population numbers. The introduction of predatory fish has also been a contributing factor. However, conservationists have implemented refuges and other schemes to help bolster their numbers once again.

In the wild, this amphibian mainly lives in deep waters where there is abundant vegetation, but occasionally surfaces for air. In captivity, the axolotl is relatively abundant^[1]. This is, in part, due to their extensive use in research as they have the ability to regenerate body parts. The hope has always been understanding this ability will help humans to one day do the same^[2].

The axolotl is easily distinguished by its peculiar (and adorable) physical characteristics:

• Elongated body that can reach up to 30 cm in length.
• A total of 6 external gills which reside behind the top of their head, absorbing oxygen and expelling carbon dioxide.
• Small black eyes.
• Smooth, soft and elastic skin.
• Fine elongated fingers.
• Retractable tongue.
• Tiny teeth arranged in rows.
• Large buccal cavity (mouth).
• Flat tail which serves as a fin to swim.
• Visible blood vessels.

In the wild, the color of axolotls can vary between brown, green and gray, often having specks of darker colors. In captivity, we can find clear and albino variations such as the pink or golden axolotl.

Finally, regarding reproduction of the axolotl, they become sexually mature around the age of 12 to 18 months. Once a year, females lay around 100 to 300 eggs and attach them to rocks or aquatic vegetation. The offspring are born between 10 and 14 days later and begin their life without the assistance of their parents.

As with many animal species we keep as pets, some require less expert care than others. This isn't to say all pets don't need love and attention, but some companion animals have specific requirements to which not everyone is able to cater. You can have an axolotl as a pet, but they are not for everyone. Considered an exotic pet, they have a delicate physiology which means their environment needs to be carefully controlled.

There are some general guidelines which can help us looking after an axolotl. They are designed to help us look after these amphibians without causing damage to their delicate skin and very sensitive gills (without the latter they will not be able to breathe). These guidelines include:

• Each axolotl should have their own tank which should be a minimum of 10 gallons. However, ideally they should have a 20 gallon tank or bigger. They grow to around 6 to 15 inches long, although they don't usually grow over a foot. They like to roam and need the space to do so. You should never keep axolotls with other animals as they are very delicate and even small fish can nip and tear their skin.
• Juvenile axolotl need to be reared in separate tanks as they can eat each other. When they are adults, they can be put into the same tank, but will need close monitoring as they may attack.
• Axolotls need to stay in cool dark tanks. The temperature of the aquarium should be around 14.5ºC (58ºF) and well-maintained. You can have some lighting, but it can't be bright and there needs to be dark places for them to seek refuge.
• Axolotl have very sensitive skin. They are not hard-skinned reptiles and if their skin is damaged, it can be fatal. Their gills in particular are very sensitive, so even picking them up can cause them damage. Don't pick them up by hand, but use a soft net to transfer them.
• Keep tanks covered as they can jump out of them. Have a rock or similar structure sticking out of the water in case they want to be on land for any length of time.
• Chlorine can be very damaging to axolotls. For this reason, you will need to be very careful with the water you put in the tank. Often tap water is chlorinated, so you may need to use another type of water (an expense you will need to consider). This should be hard water, as water which is too soft can also be damaging.
• You should remove 20% of the water in the tank each week and replenish it with fresh water. Filters need to be well covered to prevent the axolotl getting caught. Also, axolotl have been known to ingest gravel which can cause significant problems to their well-being, so use large gravel for the substrate.
• As we state above, the chemical makeup of the water is vital for their health. The salt content is particularly imperative and there is a formula which can be used to get it right. This is known as the Holtfreter's solution^[3] and it requires (per liter of water):
  
  1. Sodium chloride (NaCl) - 3.46g
  2. Potassium chloride (KCl) - 0.05g
  3. Calcium chloride (CaCl2) - 0.1g
  4. Sodium bicarbonate (NaHCO3) - 0.2g
  
  

The axolotl is a wonderful pet, especially as they can be so adorable. However, they are not for someone who wants interaction, nor are they suitable for those who don't have the time or resources for their upkeep. They are also not legal everywhere, so you will need to check before you purchase one. If you buy them in a region where they are illegal, you will be supporting bad practices which may not protect the animal's best interests.

The axolotl is an amphibian with a carnivorous diet. Their teeth allow them to grab their food, but not to tear or chew it. This means they have to swallow their food whole. When they spot their prey in the wild, the axolotl opens their mouth to very wide dimensions and sucks in water along with their food.

Their food can be differentiated by live and dry types:

• Live food: small crustaceans, worms, earthworms, slugs, snails, crickets, mosquito larvae, frog tadpoles, occasionally small fish and other organisms as may be found in Mexico's Lake Xochimilco.
• Dry food: in captivity, it is likely you will need to offer the axolotl dried shrimp or other foods which you might offer to turtles or large fish. However, you should not give them flakes or fish food which will drop to the bottom of the tank. This is because it encourages them to eat the substrate which can be problematic.

In a supplementary capacity, you should also offer the axolotl pieces of cooked meat such as chicken, chicken liver or beef. Although these animals can handle fasting for up to weeks at a time, it is recommended you feed them at least once or twice a week.

While we have provided some practical information about how to care for a pet axolotl, there is much more to this incredible creature in the wild. Here are some interesting facts about the axolotl in case you want to know a little more:

1. Unlike most amphibian species, the axolotl reaches adulthood without metamorphosis.
2. They have both simple lungs and gills. The lungs mean they can breathe on land, but this should not be for extended periods of time.
3. They can also breathe through their skin.
4. They have very expressive eyes, but lack eyelids.
5. Their name means ‘water-dog’ from atl meaning “water” and xolotl meaning “dog”.
6. They are well renowned in Mexican folklore and the word xolotl comes from the god of the same name. In Mexican mythology it was believed this god would sometimes transform into the axolotl to hide from danger.
7. While it is relatively uncommon, it is possible for axolotls to live up to 20 years in captivity, while they are more likely to survive a maximum of 6 years in the wild.
8. The species has been used for medical studies and even in ancient rituals.
9. While they may not look very tasty, they were also a food source for indigenous Mexican peoples.
10. Their natural predators are the tilapia fish and the white heron, although their biggest enemy has been humans.

If you have any of your own interesting facts about axolotls, please feel free to leave us a comment below to share with the community.

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