Axolotl Care Guide

The axolotl (Ambystoma mexicanum) is a Mexican salamander that never leaves the larval stage. It lives its whole life underwater, breathing through its feathery external gills. Care comes down to cold, clean, still water and a bare or coarse-bottomed tank, and the hardest part for most homes is keeping the water cool. Axolotls are Critically Endangered in the wild, but pet animals are captive-bred.

Care requirements

Need	What to provide
Enclosure	Filtered freshwater aquarium. A rule of thumb is two adults per 10 gal (38 L) tank. Use slow water flow, hiding places, and a bare floor or coarse gravel only (University of Kentucky; VCA)
Temperature	60–65°F (15–18°C). Never above about 72°F (22°C). No heater (University of Kentucky)
Lighting	Keep it dim, out of direct sunlight, with shaded hides (VCA; University of Kentucky)
Diet	Carnivore: sinking salmon or trout pellets, earthworm pieces, bloodworms, blackworms and brine shrimp. Feed adults every 2–3 days, as much as they eat in 2–5 minutes (VCA; University of Kentucky)
Lifespan	10–15 years in captivity (VCA)
Social needs	Can live alone. Adults of similar size can share a tank, but young axolotls bite each other and eat smaller tankmates (University of Kentucky)
Legal notes	No common restrictions; check local rules. Wild axolotls are Critically Endangered, so buy captive-bred animals only (San Diego Zoo)

Keeping the water cold

Temperature is the axolotl’s biggest risk. The University of Kentucky’s Ambystoma Genetic Stock Center has supplied research axolotls since the 1950s. It keeps its animals at 60–65°F (15–18°C) and says they “should never be kept above about 22°C (72°F)”. VCA adds that above 75°F (24°C) axolotls become sluggish, float uncontrollably and pick up bacterial and fungal infections.

That means:

• No aquarium heater. A normal tropical setup is the wrong one for this animal.
• Choose a cool spot. Use a room away from windows, radiators and appliances, and keep the tank out of direct sun.
• Plan for summer. If your room regularly goes above 72°F (22°C), you need active cooling. An aquarium chiller is the dependable option. Fans blowing across the water surface are a common stopgap. Put a thermometer in the tank and check it daily during warm weather.

Bright light also stresses axolotls. VCA recommends dim lighting. A planted tank or caves give the axolotl shade.

Water chemistry and flow

Axolotls rely on their skin as their main defence against infection. The University of Kentucky warns against soft or distilled water: they need hard water. Keep pH between about 6.5 and 8 (University of Kentucky). Dechlorinate all tap water, including chloramine-treated water. At the high end of that pH range, ammonia becomes more toxic, so test for it more often.

Run a cycled biological filter that converts ammonia and nitrite. Keep the outflow gentle, because strong current stresses axolotls and can damage their gills (VCA). Spray bars, sponge filters or a baffled outlet all work. Axolotls spend most of the day lying still on the bottom and don’t need a fast-moving tank. Do regular partial water changes and remove uneaten food promptly. VCA notes that excess nitrite can make an axolotl’s eyes bulge.

Substrate and feeding

Axolotls feed by suction. They open their mouths and inhale whatever is in front of them, including gravel. VCA lists swallowed pebbles as a cause of intestinal blockage. The University of Kentucky notes pea-sized gravel is a particular problem and says any gravel should be coarse. A bare glass floor is the simplest choice.

For food, the University of Kentucky raises its animals on sinking salmon pellets. It also lists earthworms (“a favorite”), bloodworms, water fleas and mosquito larvae. Feed juveniles daily, and from about one year old cut back to three or four feedings a week (University of Kentucky; VCA). Obesity is common in pet axolotls and shortens their lives (VCA). Feeder fish are risky: any live fish should be aquarium-bred, and bait-shop minnows “are usually heavily infested with parasites” (University of Kentucky).

Gotchas

• Treating it like a tropical fish. A heater, or a tank in a warm room, pushes an axolotl into the temperature range where it stops eating and gets infections (VCA; University of Kentucky).
• Pea-sized gravel or small pebbles. Axolotls swallow them while feeding, and they can cause a gut blockage (VCA).
• Mixing sizes. Young axolotls snap at anything that moves. Larger ones eat smaller ones, and tankmates of mixed sizes end up missing toes and feet (University of Kentucky).
• A powerful filter outlet. Constant strong current stresses the axolotl and damages its gills (VCA).
• Distilled or RO water on its own. Soft water weakens the skin’s defences. Remineralise it or use hard, dechlorinated tap water (University of Kentucky).

Avoid

• Aquarium heaters and tank spots in direct sunlight
• Small gravel, pebbles, marbles or any decoration small enough to swallow
• Bait-shop minnows and wild-caught feeder fish, which carry parasites
• Untreated tap water containing chlorine or chloramine
• Strong water flow from filters or air stones
• Small fish as tankmates: axolotls eat small fish (San Diego Zoo)
• Handling beyond what you need for tank cleaning: rough handling can cost a limb (VCA)

Signs to see a vet

The first signs of illness in axolotls are loss of appetite and deteriorating gills, according to the University of Kentucky. Seriously ill animals may also show skin sores, yellowing or swelling. Other red flags are floating that it can’t control, bulging eyes, or refusing food for more than a few feedings. Check water temperature, ammonia and nitrite first, then see a vet experienced with amphibians (VCA; University of Kentucky).