Axolotl, or Mexican Walking Fish, Care
The axolotl commonly goes by the names Mexican walking fish or Mexican salamander, despite not being a fish (it’s an amphibian) and being highly unusual from other salamanders. This is because axolotls are neotenic, meaning that they remain in their larval stage their entire lives, never losings their gills or tails. It’s thought that axolotls evolved (or de-evolved) to became neotenic as a result of the higher comparative safety of remaining in the mountainous lakes their whole lives over risking life on land. They are very closely related to the Tiger Salamander, a terrestrial cousin.
Today, axolotls are critically endangered in the wild, but commonly bred in captivity. A major reasons for its prominence in captivity is the common use of axolotl tissue in laboratory experiments, due to its powerful regenerative abilities. Axolotls are capable of regrowing an entire limb in the event that it is lost - though, obviously, it is not recommended that you test this out with your pet. They also make popular exotic pets due to their unique appearance and hardiness.
Captive axolotls come in a variety of colors, including wild type (green, brown, black with gold flecks), melanoid (like wild types, but darker and without gold flecks) leucistic (white and pink, with black eyes), albino (white and pink, with clear or red eyes), and golden albinos (pale yellow)
Scientific name: Ambystoma mexicanum
Family: Ambystomatidae (mole salamanders)
Distribution: Lake Xochimilco and (formerly) Lake Chalco in central Mexico
Temperament: Axolotls are not social animals, and it is not recommended to keep multiple together. Juvenile axolotls are liable to attack and eat each other, and even mature adults may still nip and harm one another. In addition, being a voracious carnivorous animal, axolotls do not make good tank companions for fish, shrimp, and other aquatic animals.
Diet: Axolotls are carnivorous and captive pets may be fed a number of options, live and dead, including:
- Brine shrimp
- Pellets for salmon
Lifespan: 10-15 years, but capable of living up to 20
Adult size: Up to 12 inches
Tank size: For a single juvenile axolotl, a 10-gallon tank is the minimum size, though for a full-grown adult you will need at least 20 gallons. It is more important that the length is large enough than the height, as axolotls will primarily rest at the bottom of the tank.
Temperature: 60-65 degrees Fahrenheit (never above 75 degrees Fahrenheit)
Axolotls are endemic to two lakes in central Mexico: Lake Xochimilco and Lake Chalco, before the latter was drained in an effort to prevent flooding. Wild axolotls in Lake Xochimilco are also nearing extinction due to worsening water quality, with only 35 per square kilometer being counted in 2015 - a rapid drop from the formerly 6,000/sq. km. two decades ago.
The water in these lakes is cool, with temperatures of between 54 to 68 degrees year-round. Axolotls prefer moderately hard water as a result of their natural habitat, so be cautious if the water in your home is very soft. The lakes are slow-moving, and axolotls are liable to become very stressed if the water movement in your tank is too rapid.
Tank Size - 20 gallons or above for a single adult (10 gallons is the minimum for a single juvenile)
Decor - Provide aquarium-safe hiding places for your axolotl to go in order to help minimize their stress (such as a terra cotta pot). Plants (live or fake) are also a good idea to decorate your aquarium and provide hiding spaces for your axolotl, though they are not necessary. Avoid sharp plastic plants that they may cut themselves on.
Substrate - It is recommended that you provide a substrate for your axolotl, as they can become stressed by a bare-bottomed tank, unable to move easily due to poor grip. If you choose to use gravel, be careful to select a large enough gravel size that it does not pose a choking hazard for your pet. Sand is a widely-used option, because of its ability to pass through an axolotl without any harm and provides solid grip for your axolotl to move freely.
Lighting - Axolotls are fairly light-sensitive and thus it's preferable to use natural or dim lighting in their tanks. It's also a good idea to avoid bright lights because it may heat up the water above the cooler temperatures that axolotls prefer.
Equipment - While water filters are useful in aquariums in order to harbor beneficial bacteria, to oxygenate the water, and to remove particles from the water, axolotls are sensitive to strong water flows. Use a gentle water filter, such as a sponge filter, for your axolotl so their gills and appendages aren't harmed.