After keeping and studying axolotls for eight years, I still find these creatures absolutely fascinating. When people see my axolotls for the first time, they always ask the same question: “What exactly is that?”

What Is an Axolotl? The Basic Definition

An axolotl is a type of salamander that lives its entire life underwater. Unlike other salamanders that eventually develop lungs and move onto land, axolotls stay in their larval form forever.

The scientific name is Ambystoma mexicanum, and they belong to the amphibian family. They’re native to Mexico and have become popular pets worldwide over the past few decades.

Here’s what makes them unique: they never grow up in the traditional sense. While they reach sexual maturity and can reproduce, they keep their juvenile features throughout their entire life. Scientists call this trait “neoteny.”

Physical Characteristics: What Axolotls Look Like

The Iconic External Gills

The most striking feature of any axolotl is the feathery gills on either side of their head. These branch-like structures stick out from behind their jaw and wave gently in the water.

The gills have three branches on each side, and they come in various colors depending on the axolotl’s overall coloration. Healthy gills are full, fluffy, and stand out prominently.

What the Gills Do:

• Extract oxygen directly from water
• Indicate health status through appearance
• Act as sensory organs
• Change based on oxygen levels in water

I can tell a lot about my axolotls’ health just by looking at their gills. Stressed or sick axolotls have thin, forward-facing gills, while healthy ones have full, relaxed gills that stick out to the sides.

Body Structure and Size

Axolotls have a distinctive appearance that’s hard to mistake for anything else.

Physical Features:

• Long, flat tail (makes up about half their body length)
• Four legs with delicate toes (4 toes on front feet, 5 on back)
• Wide head with small, lidless eyes
• Broad mouth that looks like a permanent smile
• Smooth, soft skin
• Small dorsal fin running along their back

Size:

• Hatchlings: About 0.5 inches long
• Juveniles (3-6 months): 3-5 inches
• Adults: 9-12 inches on average
• Large individuals: Can reach 14-18 inches
• Weight: 2-8 ounces when fully grown

My largest axolotl measures just over 13 inches from nose to tail tip. It took about 18 months to reach full size.

Color Varieties (Morphs)

One reason axolotls became popular pets is the stunning variety of colors they come in. Through selective breeding, several distinct morphs have been developed.

Wild Type

• Dark brown or black with gold speckling
• Dark eyes
• Most similar to natural population
• Excellent camouflage coloring

Leucistic (Most Popular)

• Pink body with dark eyes
• Pink or red gills
• The classic “pink axolotl“ people recognize
• My personal favorite to keep

Golden Albino

• Yellow to golden body color
• No dark pigmentation
• Pink or red eyes
• Shimmery appearance

White Albino

• Pure white body
• Pink or red eyes
• Pink gills
• Very pale overall

Melanoid

• Solid black or very dark gray
• No gold speckling or iridescence
• Dark eyes
• Sleek appearance

Copper

• Copper-brown coloring
• Often has some iridescence
• Light eyes
• Less common morph

Chimera and Mosaic

• Split coloring (half one color, half another)
• Rare genetic occurrence
• Highly sought after
• Each individual is unique

The color morph doesn’t affect personality or care requirements. All morphs need the same conditions regardless of appearance.

The Science Behind Axolotls: Why They’re Special

Neoteny: The Peter Pan of Salamanders

Most salamanders go through metamorphosis. They start as aquatic larvae with gills, then develop lungs and move onto land as adults.

Axolotls skip this process. They retain their juvenile characteristics throughout life while still becoming sexually mature adults who can reproduce.

What Neoteny Means:

• Keep external gills their whole life
• Remain fully aquatic
• Never develop lungs (though they have rudimentary ones)
• Maintain tail fin
• Don’t develop eyelids

This trait evolved because their native habitat offered better survival opportunities in water than on land. Why struggle on land when the lake provides everything needed?

Interestingly, you can force an axolotl to metamorphose using hormones, but this process is stressful, dangerous, and significantly shortens their lifespan. It should never be done.

Regeneration Superpowers

This is where axolotls become truly extraordinary. They possess regeneration abilities that seem almost magical.

What They Can Regenerate:

• Limbs (legs, feet, toes)
• Tail
• Gills
• Parts of their heart
• Portions of their brain
• Spinal cord
• Jaw
• Skin
• Organs

I’ve witnessed this firsthand. One of my axolotls lost a leg due to aggression from a tank mate. Within four months, the leg completely regrew including bones, muscles, nerves, and skin. No scar, no deformity, perfectly functional.

Scientists study axolotls extensively because understanding their regeneration could potentially help human medicine. They’ve become important research animals in laboratories worldwide.

Breathing Mechanisms

Axolotls have three ways to get oxygen, which is pretty unusual:

Primary Method: External Gills

• Filter oxygen from water
• Most efficient method
• Always in use

Secondary: Cutaneous Respiration

• Absorb oxygen through their skin
• Skin must stay moist to work
• Supplemental to gill breathing

Tertiary: Rudimentary Lungs

• Can gulp air from surface occasionally
• You’ll see them rise up and take a breath
• Not their main oxygen source

Healthy axolotls primarily use their gills. If they’re constantly surfacing for air, that indicates water quality problems or low dissolved oxygen.

Axolotl Behavior and Personality

General Temperament

People often think fish and amphibians don’t have personality. Eight years with axolotls proved that wrong.

Each of my axolotls behaves differently. Some are bold and curious, investigating any movement outside the tank. Others are shy and spend most of their time hiding.

Common Behaviors:

• Walking along tank bottom (preferred movement)
• Occasional swimming bursts
• Sitting still for long periods
• Hunting for food with sudden movements
• Investigating new objects cautiously
• Resting in favorite hiding spots

They’re not cuddly pets. Axolotls don’t recognize owners the way dogs do. However, they do learn feeding schedules and become more active when they see you approach at feeding time.

Activity Patterns

Axolotls are primarily nocturnal, meaning they’re most active at night. During the day, they often rest in shaded areas or hiding spots.

Daily Routine:

• Morning: Usually resting or slowly exploring
• Afternoon: Minimal activity, hiding from light
• Evening: Increased activity begins
• Night: Peak activity period for hunting and exploring

I’ve adjusted my interaction schedule around their natural rhythm. Feeding in the evening yields better results than trying to feed them mid-day.

Social Behavior

Axolotls aren’t social creatures. They don’t seek companionship from other axolotls or form bonds.

Interaction Between Axolotls:

• Generally ignore each other
• May show aggression during feeding
• Can nip at gills or limbs
• Young axolotls are more cannibalistic
• Adults tolerate each other better in large tanks

I keep mine separately to avoid injuries. While some people successfully house multiple axolotls together, it requires careful monitoring and plenty of space.

Intelligence and Senses

Cognitive Abilities

Axolotls aren’t highly intelligent compared to mammals or birds, but they’re smarter than people give them credit for.

What They Can Learn:

• Recognize feeding time
• Distinguish food from non-food items
• Remember tank layout
• Anticipate when feeding will occur
• Associate your presence with food

My axolotls definitely know my feeding routine. They become active and position themselves near the front of the tank when they hear me approaching at their usual feeding time.

Sensory Perception

Vision:

• Poor eyesight overall
• No eyelids (eyes always open)
• Detect movement better than details
• Sensitive to light levels

Smell:

• Primary hunting sense
• Detect food chemicals in water
• Follow scent trails to locate prey

Lateral Line System:

• Detect vibrations and water movement
• Similar to fish sensory system
• Helps locate prey and navigate
• Senses pressure changes

Touch:

• Sensitive skin receptors
• Detect temperature changes
• Feel surfaces they walk on

They rely more on smell and their lateral line than vision for hunting and navigation.

Lifespan: How Long Do Axolotls Live?

With proper care, axolotls live surprisingly long for amphibians.

Typical Lifespan:

• In captivity with good care: 10-15 years
• Exceptional cases: 15-20 years
• Wild populations: 5-10 years (estimated)
• Poor care conditions: 2-5 years

The oldest axolotl on record lived 25 years, though this is extremely rare.

Several factors influence lifespan:

Increases Longevity:

• Proper temperature (cool water)
• Excellent water quality
• Appropriate diet
• Low stress environment
• Adequate tank size
• Regular health monitoring

Decreases Lifespan:

• Warm water temperatures
• Poor water quality
• Overfeeding or malnutrition
• Small tanks
• Aggressive tank mates
• Frequent handling

My oldest axolotl is currently 11 years old and still going strong. Keeping the water cool made the biggest difference in his health and longevity.

Reproduction and Life Cycle

Sexual Maturity

Axolotls reach reproductive age relatively quickly.

Maturity Timeline:

• Males: 6-12 months
• Females: 12-18 months (usually later than males)
• Depends on feeding, temperature, and individual growth rate

How to Sex Axolotls:

Males have a prominent cloacal bulge behind their back legs. It looks like a noticeable swelling. Females lack this bulge and have a rounder body shape when carrying eggs.

You can’t reliably determine sex until they’re at least 6 inches long.

Breeding Process

Axolotl breeding is fascinating but should only be attempted by experienced keepers.

Mating Behavior:

• Male performs courtship dance
• Deposits spermatophore (sperm packet) on substrate
• Female picks it up with her cloaca
• Internal fertilization occurs

Egg Laying:

• Female lays 100-500 eggs
• Attached individually to plants or surfaces
• Gelatinous coating protects eggs
• Incubation takes 14-21 days depending on temperature

Development Stages

Eggs (Day 0-21):

• Small, jelly-covered spheres
• Embryo visible inside
• Need good water quality and cool temperature

Hatchlings (Week 3-8):

• About 0.5 inches long
• Begin eating immediately
• Highly cannibalistic
• Need frequent feedings

Juveniles (Month 2-12):

• Rapid growth phase
• Developing adult features
• Less cannibalistic than hatchlings
• Require substantial food

Adults (1 year +):

• Sexually mature
• Growth slows significantly
• Full coloration developed
• Established behavior patterns

Raising baby axolotls requires significant effort. They need multiple daily feedings, frequent water changes, and eventually separation to prevent cannibalism.

Axolotls in Research and Medicine

Why Scientists Study Them

The scientific community’s interest in axolotls goes far beyond their cute appearance.

Research Applications:

Regeneration Studies

• Understanding how limbs regenerate completely
• Investigating stem cell function
• Exploring tissue repair mechanisms
• Potential applications for human medicine

Developmental Biology

• Studying embryonic development
• Understanding neoteny genetics
• Organ formation research

Genetics

• Genome sequencing projects
• Gene expression studies
• Evolutionary biology

Cancer Research

• Axolotls rarely develop tumors
• Studying cancer resistance mechanisms
• Understanding cell division control

Neuroscience

• Brain regeneration capabilities
• Neural pathway development
• Spinal cord injury research

Major universities and research institutions worldwide maintain axolotl colonies specifically for scientific study.

Medical Breakthroughs

Research on axolotls has contributed to several medical advances:

• Improved understanding of tissue regeneration
• Insights into organ development
• New approaches to treating spinal injuries
• Better knowledge of limb formation
• Understanding of cellular aging

Scientists hope that unlocking the secrets of axolotl regeneration could eventually help humans regrow damaged tissues or organs.

Conservation Status: Why Axolotls Matter

Critically Endangered in the Wild

While axolotls are common pets, wild populations face extinction.

Current Status:

• Listed as Critically Endangered by IUCN
• Fewer than 1,000 individuals estimated in wild
• Some recent surveys found zero wild axolotls
• Native habitat severely degraded

This represents one of the most dramatic population declines of any amphibian species.

Threats to Wild Populations

Habitat Loss:

• Urban development around Mexico City
• Lake drainage for water supply
• Canal system destruction
• Wetland conversion

Water Pollution:

• Agricultural runoff
• Industrial contamination
• Sewage discharge
• Chemical pollutants

Invasive Species:

• Tilapia and carp compete for food
• Predation on juvenile axolotls
• Disruption of ecosystem balance

Climate Change:

• Altered water levels
• Temperature increases
• Habitat degradation
• Seasonal pattern changes

Conservation Efforts

Several organizations work to save wild axolotls:

• Habitat restoration in Lake Xochimilco
• Captive breeding programs
• Educational initiatives
• Scientific research on population recovery
• Community engagement projects
• Protected zones establishment

The good news is that axolotls breed readily in captivity. Thousands exist in pet trade and research facilities worldwide. However, captive animals can’t replace the genetic diversity and ecological role of wild populations.

How Pet Owners Help

By keeping axolotls responsibly, pet owners contribute to species preservation:

• Maintain genetic diversity through breeding programs
• Increase public awareness about the species
• Support conservation through education
• Provide backup population if wild extinction occurs

Axolotls as Pets: What to Expect

Are They Good Pets?

After eight years, I believe axolotls make excellent pets for the right person.

Advantages:

• Fascinating to watch
• Long lifespan with proper care
• Unique appearance
• Relatively quiet (no noise)
• Don’t require daily interaction
• Interesting behaviors

Challenges:

• Need cool water (requires equipment in most climates)
• Require large tanks
• Sensitive to water quality
• Can’t be handled frequently
• Need specific diet
• Higher initial setup cost

They’re not beginner pets, despite what some pet stores claim. Successfully keeping axolotls requires research, proper equipment, and commitment.

Daily Care Requirements

Owning an axolotl isn’t particularly time-intensive once established.

Daily Tasks:

• Check temperature
• Observe for health issues
• Feed (adults eat every 2-3 days)
• Remove uneaten food

Weekly Tasks:

• Test water parameters
• Partial water change (20-30%)
• Clean any debris

Monthly Tasks:

• Deep clean decorations
• Replace filter media
• Check equipment function

The biggest ongoing cost is electricity for cooling equipment in warm climates.

Common Health Issues

Knowing what to watch for helps catch problems early.

Temperature Stress:

• Most common problem
• Causes lethargy, loss of appetite
• Can be fatal if prolonged

Poor Water Quality:

• Leads to fungal and bacterial infections
• Damages gills and skin
• Causes stress and disease

Impaction:

• From swallowing gravel or large food
• Causes constipation and bloating
• Can require veterinary intervention

Injuries:

• From tank mates or sharp decorations
• Usually heal through regeneration
• Prevent through proper setup

Fungal Infections:

• White fluffy growth on body or gills
• Treatable with salt baths
• Indicates poor water conditions

Most health problems stem from incorrect temperature or water quality. Get these right, and you’ll rarely face issues.

Interesting Facts About Axolotls

After years of keeping them, these facts still amaze me:

Historical Significance:

• Aztecs considered them sacred
• Featured in Mexican mythology
• Name means “water monster” in Nahuatl
• Traditional medicine ingredient historically

Biological Oddities:

• Can regenerate the same limb hundreds of times
• Have about 10 times more DNA than humans
• Can accept organ transplants from other axolotls without rejection
• Don’t get scars when healing

Cultural Impact:

• Star in Pokemon (Mudkip, Wooper)
• Featured in Minecraft
• Popular in memes and social media
• Symbol of conservation efforts

Records:

• Largest recorded: 18 inches long
• Oldest recorded: 25 years
• Most eggs laid: Over 1,000 in one clutch

Unique Abilities:

• Can change color slightly based on mood and environment
• Communicate through pheromones
• Map their territory mentally
• Sometimes play dead when stressed

What Species Are Related to Axolotls?

Axolotls belong to a group called mole salamanders (genus Ambystoma).

Close Relatives:

• Tiger salamander (Ambystoma tigrinum)
• Spotted salamander (Ambystoma maculatum)
• Marbled salamander (Ambystoma opacum)
• Blue-spotted salamander (Ambystoma laterale)

Unlike their cousins, most Ambystoma species undergo metamorphosis and become terrestrial adults. Axolotls are exceptional in remaining aquatic throughout life.

The Future of Axolotls

The contrast between their popularity in captivity and their conservation status is striking.

Captive Population:

• Thriving in pet trade worldwide
• Thousands in research facilities
• Well-established breeding programs
• Genetic diversity maintained

Wild Population:

• Facing extinction
• Limited to small habitat area
• Ongoing decline despite protection efforts
• Uncertain future without intervention

The species will likely survive through captive populations even if wild populations disappear. However, this represents a tragic loss of natural heritage and ecosystem function.

Final Thoughts on What Axolotls Are

Axolotls are truly remarkable creatures. They’re salamanders that never grow up, keeping their juvenile gills and aquatic lifestyle throughout their entire life. They can regenerate entire body parts, making them invaluable to science. They come in stunning colors that make them popular pets worldwide.

Yet they’re also critically endangered in their native Mexican lakes, facing extinction in the wild while thriving in aquariums around the globe.

After eight years of keeping these animals, my appreciation for them only grows. They’re not just cute pets or interesting research subjects. They represent something unique in the natural world a species that chose a different path, evolving to remain permanently aquatic while their relatives moved onto land.

Understanding what axolotls are means recognizing both their biological uniqueness and their conservation crisis. They need cool, clean water to survive. They require specific care that not everyone can provide. But for those willing to meet their needs, they offer a window into an extraordinary form of life.

Whether you’re considering keeping axolotls as pets, interested in their scientific importance, or simply curious about these unusual salamanders, remember that each captive axolotl connects to a larger story one of evolution, adaptation, and the urgent need for conservation.