The Axolotl, Mexico’s Aquatic Salamander
Want an unusual herp that is easy to keep? Try the axolotl. A native of Mexico, the axolotl is also known as the aquatic salamander, or the mole salamander. The axolotl is a neotenic amphibian whose scientific name is Ambystoma mexicanum. Neotinic amphibians are amphibians that do not undergo metamorphosis, under normal circumstances, from the larval to adult stages. The axolotl remains aquatic throughout its lifetime. This salamander never leaves the confines of water. Originally from the lakes underlying Mexico City, as of 2008 they are nearly extinct in their native environment due to urbanization and environmental pollution.
In rare instances and under extreme conditions the axolotl will undergo a stress metamorphosis and may become terrestrial. This metamorphosis should not be induced and is thought to decrease the life expectancy of the animal. This metamorphosis is a response to extreme conditions such as drought, when an aquatic environment is no longer available.
The axolotl is easy to care for. Water should be dechlorinated. A weekly water change of 20% is recommended to maintain the water quality. The temperature of the water should be maintained between 57° F - 68° F, or from 14° - 21° C. Colder temperatures result in a lower metabolism while higher water temperatures lead to stress and an increase in disease. The depth of the water should approximate the length of the axolotl’s body. For this species a low-current aquarium filter is recommended. A high flow of water may actually induce stress and tear or trap delicate body parts.
The skin of amphibians is highly permeable making them very susceptible to water toxins, ionized metals, changes in pH and dehydration. The pH of the water should be kept above 6.5. Systemic medications are often administered by dips.
The axolotl is a voracious predator and may be cannibalistic; therefore, do not house these animals together unless they are approximately the same size. A ten gallon aquarium is sufficient space to house only one adult animal.
This salamander spends most of its time on or near the bottom of the tank. Handling of this species is discouraged since they have very sensitive skin and gills. When handling becomes necessary an aquarium net should be used.
Cage accessories are important to provide the animal security and relieve stress. Aquarium plants (live or artificial) and caves within which to hide are a necessity.
The axolotl is nocturnal so no lighting is required, but a low wattage bulb for viewing is harmless. The tank should never be exposed to direct sunlight. The aquarium bottom may be bare or large-sized, coarse aquarium gravel may be used. Small gravel may be accidentally ingested during feeding and should not be used. Large, smooth, flat rocks may also be used on the bottom for the axolotl to explore.
This salamander has long been captive-bred in research laboratories to study their amazing ability of vertebrate regeneration. This species is known for regenerating their tail, limbs, and even other vital structures along with portions of the central nervous system including brain matter. It is hoped that by studying this species we will unlock knowledge necessary to facilitate recovery following spinal cord injuries and nerve cell damage.
In captivity the axolotl is an indiscriminant feeder and will generally eat anything it can fit into its mouth. The axolotl diet includes: brine shrimp, earthworms, trout, turtle pellets, tubifex worms, bloodworms, and waxworms. Small amounts of liver cut into strips may be used in a pinch, but since is not a native diet it should be used sparingly. Variety in the food source is one of the best ways to ensure the pet receives the correct nutrients. Uneaten food should be removed from the aquarium to prevent spoiling and thereby affect the water quality.
The axolotl does not chew its food but rather swallows it whole with a vacuum-like suction. The axolotl does have small teeth but they are used to grip its prey. Once the axolotl becomes used to its owner it will often accept being hand-fed.
In captivity five color variations are available: wild, which is mottled shades of brown; melanistic, a black coloration; leucistic, a pale color with black or bluish eyes; albino, being pink or gold with red eyes; and the final coloration, being piebald.
An adult reaches a size of 9 to 10 inches in length. These salamanders have been known to live more than 15 years in captivity.
In its native Mexico the axolotl, which was once used as a food source for the Aztecs, is now listed on the CITES endangered species list. This salamander has been bred in such high numbers in captivity that there is no danger of the pet trade having a negative effect on the wild population of axolotl; and in fact, may prove helpful in repopulating their natural habitat should environmental conditions improve near Mexico City.
Boyd, Darren. “Unique Beauty, the Axolotl, Mexico’s Aquatic Salamander, Proves a
Fascinating Pet.” Pet Product News International. August 2007. Pp. 78-79.
Exotic Companion Medicine Handbook for Veterinarians. Amphibians 1-15.
“Salamander’s Regenerative Capabilities Under Study.” Veterinary Practice News. February 2010. P. 16.