Mexican Axolotl (Ambystoma mexicanum) – an amphibian with special requirements
The Mexican axolotl (Ambystoma mexicanum) is an unusual tailed amphibian that is gaining popularity among aquarists. Its appearance and fascinating features make it an object of interest for many aquarium animal enthusiasts. Unfortunately, the lack of reliable information in pet stores and the improper care of many owners make axolotls suffer. In this post, I will introduce the specific requirements of the axolotl and explain how much responsibility rests on its caretaker.
Where do axolotls live?
The Mexican axolotl (Ambystoma mexicanum) is an endemic species found only in the canals of Lake Xochimilco in Mexico, located at an altitude of 2240 meters above sea level. The water there is surprisingly cold, reaching a maximum of 17°C. Additionally, the slushy waters flowing down from the mountains provide a lot of minerals, which contributes to the significant hardness and alkalinity of the water. The bottom of the channels is covered with silt, and the vegetation consists of typical species found in ponds and wetlands.
Unfortunately, the degradation of the axolotl’s natural habitat through land drainage for road construction, stocking of the lake with foreign fish species, and water pollution have led to a significant reduction in the population of these animals. They are now found mainly in six specially protected sites on Xochimilco. Due to the drastically declining population, the Mexican axolotl is covered by the Washington Convention CITES (Appendix II) and is listed on the Red List of endangered species. Read more Axolotl (Ambystoma mexicanum) – Treasure from Lake Xochimilco. Therefore, when you buy this fascinating amphibian, you will receive documents confirming its origin and must register it with the appropriate authority.
What does an axolotl look like?
The axolotl is a neotenic amphibian, meaning it retains its larval form throughout its life and does not transform into an adult form. This unique phenomenon is due to a congenital insufficiency of the thyroid gland, which prevents it from transforming normally into a terrestrial salamander. Nevertheless, under certain laboratory and environmental conditions, axolotls can undergo transformation.
An axolotl has two pairs of limbs, a prominent tail, and a dorsal fin extending from the tail to the head. The head is flat, with unpupulated eyes on either side. Three gill arches on each side of the head contain fluffy gill filaments, which play a key role in gas exchange. Axolotls perform gas exchange in three different ways. The primary method is respiration through the gills, where oxygen is absorbed by red blood cells and carbon dioxide is released into the surrounding water. The efficiency of this exchange depends on the fullness and fluffiness of the gill fibers.
Like other amphibians, axolotls can also absorb oxygen and release carbon dioxide directly through their mucus-covered skin. However, their skin does not have a sufficient surface area to meet the body’s oxygen needs and maintain health and activity. In addition, axolotls use their underdeveloped lungs for respiration. To do this, they swim below the surface to draw in atmospheric air.
Thermal requirements of Mexican axolotl (Ambystoma mexicanum)
To ensure a long, healthy life for these amphibians (which can live up to 12 years), it is crucial to maintain an appropriate water temperature in the tank, which should not exceed 17°C. Higher temperatures make axolotls susceptible to disease, with symptoms often appearing suddenly in the form of thrush or dangerous bacterial infections. Therefore, immediate action is necessary, as axolotls signal diseases relatively late and do not feel the gradual increase in temperature. An indispensable piece of equipment for an aquarium where axolotls reside is an aquarium refrigerator, which can maintain a constant low temperature within a safe range. The lack of this device can make it impossible to maintain the right temperature in the summer and during the heating season.
How to arrange an aquarium for an axolotl?
When choosing an aquarium for axolotls, the main consideration is the area of its bottom. An aquarium of 80×35 cm is sufficient for a pair of axolotls. The preferred height of the tank is 30-45 cm. Due to their tendency to jump above the water surface under stress, it is recommended to use a cover or maintain at least a 5 cm distance from the water surface to the edge of the aquarium.
Axolotls kept in captivity swallow small stones. Therefore, it is necessary to use quartz sand of a size not exceeding 2 mm as a substrate. Swallowed grains of this size can be easily excreted by the axolotl. Young axolotls (up to 12 cm) are recommended to be kept in an aquarium without a substrate. It is also advisable to avoid larger stones, which can accumulate difficult-to-remove dirt. Remember that axolotls are carnivores and produce a lot of feces. An important part of the aquarium equipment is hiding places, which should be numerous and of different shapes. Avoid ornaments with sharp edges, as axolotls can easily injure their delicate skin.
Filtration in a tank with axolotls
Filtration should be effective and include beds for biological filtration. Since axolotls inhabit still waters, too much water current can stress them. The solution is to disperse the outflowing water with a rain shower, mimicking more natural conditions. Since axolotls enjoy an abundance of oxygen in their natural habitat, it is a good idea to include additional aeration, such as using an aeration stone.
Plants in an aquarium with axolotls
Plants are an important element in an aquarium, as axolotls love to hide among them. An aquarium without plants can make axolotls feel threatened and stressed. Research indicates that in the wild, these amphibians avoid areas devoid of vegetation. Cold-loving species such as hornwort, Elodea or eelgrass are best for planting. Floating plants can also be used.
How to light an aquarium for axolotls?
The lighting of the aquarium should not excessively heat the water or be too intense. If the lighting is stronger, it is advisable to place floating plants to create shaded areas where axolotls can take refuge. Since axolotls do not have eyelids, strong light can irritate their eyes, and the sudden switching on of an intense lamp often leads to panic. LED lamps that allow you to program sunrise and sunset are a good solution.
Chemical parameters of water in an aquarium with axolotls
Mexican axolotl (Ambystoma mexicanum) are very sensitive to abnormal water parameters. They have a low tolerance to elevated nitrate concentrations (above 50 ppm) and are not resistant to nitrite and ammonia in the water, which can cause gill and skin burns. Therefore, maintaining proper water parameters is crucial. The water should be moderately hard, in the range of 8-14°GH, and the pH should not fall below 6.5. Using nitrifying bacteria, such as Tropical Nitri-Active, is also recommended when setting up an aquarium for axolotls.
Companionship for axolotls
Axolotls are extremely social creatures, so it is recommended to keep them in pairs at least. The sex does not matter, but when keeping individuals of both sexes, be aware that females should not spawn more than three times a year. Note that sex differentiation is possible only after about 18 months of age. These animals do not exhibit territorial behavior, and conflicts are usually due to a too-small aquarium, insufficient food, or poor eyesight reacting to movement.
Due to their predatory nature, it is not recommended to keep axolotls with fish, which may become a snack for them or cause injury. Species such as Loricariidae or Corydoras can damage an axolotl’s skin and strip it of its protective mucus. If an axolotl swallows one of these fish, it becomes virtually impossible to remove it from the esophagus without veterinary intervention. Fish such as barbs, botias, Callichthyidae, or larger species like cichlids can bite the limbs and gills of the axolotl, reducing the surface area available for respiration and opening the way for bacteria. Additionally, tropical fish will not fare well at the low temperature (17°C) preferred by axolotls, leading to their diseases and infections, which put the axolotls at risk.
Other amphibian species in a tank with axolotls carry the risk of conflicts, mutual injury, and transmission of infections. Snails can be ingested, leading to a clogged digestive system and carrying parasites dangerous to axolotls. Therefore, the only suitable company for an axolotl is another axolotl.
What preparations to avoid?
When caring for axolotls, avoid using preparations containing copper and malachite green. Treat the use of salt and methylene blue as a last resort. It is also not recommended to use water conditioners containing aloe vera due to reports of its irritating effects on skin and gills. Although this is not scientifically confirmed, some individuals may be more sensitive or other factors may affect skin irritation. Agents that neutralize chlorine, such as Tropical Antychlor, are safe and recommended during water changes.
Regeneration
The Mexican axolotl is known for its impressive ability to regenerate lost body parts. However, the regeneration process requires sterile conditions and the use of anti-inflammatory drugs, painkillers, or antibiotics when necessary. Although regeneration itself takes a relatively short period, treating disease in an axolotl is a painstaking process that should be monitored by a veterinarian, especially in the case of deep wounds or extensive burns, which can be prone to bacterial or fungal infections.
What do axolotls eat?
Axolotls are strict carnivores. In the wild, they eat zooplankton, small fish and frogs, tadpoles, crayfish of the genus Camberellus, water striders, Oligochaetes, and sometimes insects that fall on the water’s surface. Rarely, algae or pieces of aquatic plants find their way into their stomachs.
Numerous cross-breedings with other ambystoma species and years of captive breeding have contributed to changes in their dietary needs, the composition of the bacterial flora of their digestive system, and even the way they digest food. According to recent studies, axolotls fed an unchanged diet grew and developed much faster than those on a mixed diet. Researchers suggest that for this species and probably other amphibians, an unchanging diet of good quality is a better strategy than a mixed diet. Therefore, well-balanced pellets should form the basis of the diet for axolotls.
Many good pellets are available in pet stores, providing everything the axolotl’s body needs, taking into account daily energy requirements, body weight, physiological state, and living conditions. According to recent research, good food for axolotls should have a maximum of 45% protein.
They can be fed pellets like Tropical Soft Line America size L and Tropical Gel Formula for Carnivorous Fish. As a treat, freeze-dried products such as tubifex (Tropical Tubi-Cubi), artemia (Tropical FD Brine Shrimp), or fish fillets in cube form are recommended. Young axolotls up to about 8 months of age should be fed daily, while older individuals can be fed 2-3 times a week. Food can be dropped freely on the bottom of the aquarium for axolotls to find using their very sensitive sense of smell.
What not to feed axolotls?
Feeding only Dendrobaena, fish, and other raw ingredients can lead to nutrient deficiencies or excesses (mainly vitamins and minerals). Fish provide a relatively high amount of phosphorus and little calcium, so the wrong amount in the diet can lead to calcium-phosphorus disorders. Do not feed axolotls crickets, cockroaches, mealworms, or woodworms, as these insects contain a lot of chitin, which can lead to gastrointestinal problems. Some insects can even cause perforation of the digestive system due to their sharp body parts. Additionally, these foods have an inadequate calcium/phosphorus ratio, leading to Metabolic Bone Disease (MBD) in axolotls. MBD results from a calcium-phosphorus imbalance in the amphibian’s body, leading to weakened bone structure and various health issues.
Axolotls should also not be fed white fly larvae (maggots), as they are too fatty and can survive in the anaerobic conditions of the axolotl’s digestive system, causing damage. Avoid feeding axolotls meat and offal of mammals and birds, as these are difficult for them to digest and can lead to excessive iron accumulation in their bodies, causing health issues.
Is the axolotl the animal for you?
If you have read this entire text carefully, you already know that the Mexican axolotl (Ambystoma mexicanum) is a demanding animal and not suitable for a beginner terrarium hobbyist. Taking care of it requires knowledge of aquarium basics. You also need to know how to maintain the biological balance in the aquarium and have time for systematic observation. Axolotls are delicate and signal problems quite late, so even the slightest deviation from the norm in their appearance or behavior should be a cause for concern and action.
These amphibians are not suitable for breeding in social aquariums due to their thermal requirements and predatory nature. They need shelters, plenty of room to move freely, and lush vegetation in the aquarium. Axolotls are curious and social creatures. They can rejoice at new elements in the tank or the arrival of a new flock member. These behaviors are fascinating, especially in larger groups. Therefore, you can create ideal conditions for axolotls only in a single-species aquarium. Those interested in breeding axolotls should seriously consider whether they can provide the right conditions for the animal.
