Temperatures above 24 °C (75 °F) are very stressful to axolotls. Such temperatures cause metabolism to increase (the rate at which the body "works"), and consequently, an increase in appetite. However, the stress resulting from more than a day or two of exposure to these temperatures will quickly lead to disease and death. You can read more about axolotl diseases and their treatment on the Health Page.
Transforming your aquatic friend into a land-dweller might seem cool, but leave it to the professionals; Axolotl.org strongly urges owners to never interfere with their pets’ biology, because it will likely be fatal.
John Clare is the author of Axolotl.org, and the founder of Caudata.org and FrogForum.net.
Here are several approaches to minimise concentrated water flow, such as that typical of a filter's outflow:
In captivity, axolotls eat a variety of readily available foods, including trout and salmon pellets, frozen or live bloodworms, earthworms, and waxworms. Axolotls can also eat feeder fish, but care should be taken as fish may contain parasites 
Axolotls have barely visible vestigial teeth, which would have developed during metamorphosis. The primary method of feeding is by suction, during which their rakers interlock to close the gill slits. External gills are used for respiration, although buccal pumping (gulping air from the surface) may also be used to provide oxygen to their lungs.
They look like spilled candy. You'll be tempted to scoop one up and cup it in your hands. But let it go, because the red-eyed tree frog's life is an extraordinary journey.
While you might see plenty of white ones in captivity, the animal is normally greenish brown or black. White ones are known as “leucistic” and descend from a mutant male that was shipped to Paris in 1863. They were then specially bred to be white with black eyes (different from albinos, which generally have red eyes).
Go underground and meet this salamander that's both large and common, yet so secretive it’s rarely seen.
The wild population has been put under heavy pressure by the growth of Mexico City. The axolotl is currently on the International Union for Conservation of Nature's annual Red List of threatened species. Non-native fish, such as African tilapia and Asian carp, have also recently been introduced to the waters. These new fish have been eating the axolotls' young, as well as its primary source of food.
I use Aquarium Pharmaceuticals' Stress Coat, which also contains aloe vera, a plant extract that, although slightly toxic, replaces the natural slime coat that fish have. It seems to have a similar benefit for axolotls and it's not harmful. Hagen's Amquel also contains aloe vera. Aloe vera also has a slight anti-biotic effect.
See turtles, chameleons, frogs and more from Joel Sartore's Photo Ark.
It’s not unusual for amphibians to be able to regenerate, but axolotls take it to the next level. On top of being able to regenerate limbs, the animal can also rebuild their jaws, spines, and even brains without any scarring. Professor Stephane Roy of University of Montreal explained to Scientific American:
Nitrite, NO2-, is produced from ammonia by the bacterium Nitrosomonas. It is not as toxic as ammonia, but should also be tested for regularly. Again, test kits are available and should be used about as regularly as ammonia tests.
Every time you change the water using tap water, be sure to treat it first for chlorine and chloramines. If for some reason you're unsure of the presence of chlorine in the water, you can obtain a chlorine test kit from your local aquarium shop.
Unlike some other neotenic salamanders (sirens and Necturus), axolotls can be induced to metamorphose by an injection of iodine (used in the production of thyroid hormones) or by shots of thyroxine hormone. The adult form resembles a terrestrial plateau tiger salamander, but has several differences, such as longer toes, which support its status as a separate species.
Neoteny means that a creature can reach maturity without going through metamorphosis. In less extreme cases, it’s simply exhibiting juvenile traits after reaching adulthood. Axolotls are a great example of neoteny because as they grow bigger, they never mature. Unlike tadpoles or similar animals, axolotls hold on to their gills and stay in the water, despite actually growing lungs.
Unfortunately, results so far have shown that the process might be even more complicated than expected. The scientists worry that humans might not even have the necessary genes to successfully regenerate. But there's a silver lining: While regrowing limbs might not be on the table, future studies can shed some light on smaller healing techniques.
Cannibalistic tendencies are much reduced in adult axolotls. However adults will predate upon considerably smaller axolotls, so keep different generations apart until they all reach adulthood.
A four-month-long search in 2013 turned up no surviving individuals in the wild. Previous surveys in 1998, 2003 and 2008 had found 6,000, 1,000 and 100 axolotls per square kilometer in its Lake Xochimilco habitat, respectively.
Before the axolotl was an endangered species, Xochimilco natives would chow down on the salamanders. Axolotl tamales were a favorite, served whole with cornmeal. In 1787, Francesco Clavigero wrote that, "the axolotl is wholesome to eat, and is of much the same taste with an eel. It is thought to be particularly useful in cases of consumption.”
Axolotls are large salamanders that come from the remnants of lakes Xochimilco and Chalco in Mexico City, Mexico. Axolotls live their entire lives in water, never emerging onto land. Axolotl care requirements are minimal, and provided temperature and water flow are well controlled, they are hardy, easy-to-care-for captives that breed readily in captivity. It is difficult to think of a more unusual display animal than the axolotl, and its bold and tame nature makes it an interactive pet.
Due to the tendency of nipping, fish should not be kept with axolotls. In fact, an axolotl aquarium should contain only axolotls!
Axolotls are often available from private breeders, often via the Internet. Axolotls are not commonly available in reptile stores or at reptile shows, owing to their incompatibility with most reptile-friendly temperatures. Some suppliers may be able to special order them for you, but generally the best sources for healthy axolotls are other hobbyists.
The ideal substrate for axolotls is aquarium-safe sand. Axolotls have a bad habit of ingesting gravel and mouth-sized objects if they are available. This can lead to gut impactions and the death of the axolotl. If you wish to use gravel, consider large pebbles instead. Anything the size of an axolotl’s head or smaller can and will be consumed!
The Mexican axolotl (pronounced ACK-suh-LAH-tuhl) salamander has the rare trait of retaining its larval features throughout its adult life. This condition, called neoteny, means it keeps its tadpole-like dorsal fin, which runs almost the length of its body, and its feathery external gills, which protrude from the back of its wide head.
To summarise tank cooling, the three things you need to worry about are:
Nitrate, NO3-, is the least toxic of this family of nitrogenous compounds. It is produced from nitrite by the bacterium Nitrobacter. Although it should be tested for, regular water changes and plants in the aquarium will keep the levels of nitrate in check. Although not toxic at low levels, if let build up through lack of water changes, it too can be dangerous, and high levels usually lead to blooms of algae.
There are no absolutes here. We just have to minimise the stress caused by these factors as best we can. I have a very clear opinion on temperature problems: I feel that if one can't maintain stress-free conditions for 360 of the 365 days of the year, one shouldn't keep axolotls.
As is the case with most salamanders, axolotls have no need of vitamin/mineral supplementation, and indeed it would be hard to deliver this to an aquatic animal. In my experience, axolotls fed solely on nightcrawlers will never develop any vitamin or mineral deficiencies.
The Axolotl's real world ability to regrow limbs served as the inspiration for the Tleilaxu axlotl tanks in the fictional Dune universe created by Frank Herbert.
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“The one thing that neotenic species have as an advantage is that if you don’t undergo this metamorphosis, you’re more likely to reproduce sooner. You’re already one step ahead,” biologist Randal Voss told WIRED.
Salts, such as Holtfreter's solution, are usually added to the water to prevent infection.
If you've been reading the pages in sequence, you will have read on the Housing Page that the optimum temperature for axolotls is between about 16 °C and 18 °C (60-64 °F). Lower temperatures lead to sluggish behaviour, slower metabolism, and decreased appetite. Axolotls do not hibernate, so it is not helpful to cool them below 10 °C, although they shouldn't suffer unduly if kept at these lower temperatures.
The Salk Institute for Biological Studies is studying how regeneration works in animals like axolotls, and released two studies in 2012 with their findings. The hope is that if we can fully understand regeneration, we can recreate the phenomenon in human beings.
Water flow is usually caused by a filter or when you use an air pump on an aquarium. Output from a filter can cause significant flow and this is perhaps the most common cause of stress in axolotls. Excessive water flow will, sooner or later, lead to disease. The photos below depict an axolotl that has succumbed to the stress caused by excessive water flow.
Vilem Laufberger of Germany used thyroid hormone injections to induce an axolotl to grow into a terrestrial adult salamander. The experiment was repeated by Englishman Julian Huxley, who was unaware the experiment had already been done, using ground thyroids. Since then, experiments have been done often with injections of iodine or various thyroid hormones used to induce metamorphosis.
Chlorine is a nasty green gas, denser than air, that was used in the trenches in World War I. It was dangerous enough to kill people by reacting vigorously with lung tissue. This alarming property is used to kill bacteria in municipal water supplies around the world today, which makes the water safe for human consumption.
Axolotls are members of the Ambystoma tigrinum (tiger salamander) complex, along with all other Mexican species of Ambystoma. Their habitat is like that of most neotenic species—a high altitude body of water surrounded by a risky terrestrial environment. These conditions are thought to favor neoteny. However, a terrestrial population of Mexican tiger salamanders occupies and breeds in the axolotl's habitat.