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Invasive Fish That Walk on Land and Climb Trees: Nature’s Aquatic Escape Artists

Some fish aren’t just skilled swimmers—they navigate land and even seek refuge in trees, revealing astonishing survival adaptations.

By Medha deb

Created on Sep 27, 2025

Some fish aren’t just skilled swimmers—they navigate land and even seek refuge in trees, revealing astonishing survival adaptations.

When people imagine fish, visions of streamlined bodies gliding effortlessly through water typically come to mind. Yet, scattered across rivers and wetlands, some remarkable fish have evolved to escape their aquatic world: these creatures slither over mud, traverse drought-stricken ground, and astonishingly—in rare instances—climb up trees. Their unique adaptations allow them to survive, thrive, and sometimes wreak havoc far beyond their watery homes.

Evolutionary Adaptations: How and Why Fish Leave Water
Notorious Land-Walking Invasive Fish
Fish That Scale Trees: Fact Versus Fiction
Ecological Impact of Land-Walking Fish
Humans, Ecology, and the Spread of Invasive Fish
Frequently Asked Questions (FAQs)

Evolutionary Adaptations: How and Why Fish Leave Water

The ability for some fish to venture onto land has evolved independently in several lineages. These adaptations are not feats for show—they address persistent survival challenges posed by fluctuating environments:

Breathing Atmospheric Oxygen: Many air-breathing fish have developed special organs—like labyrinth organs or modified gill chambers—that enable them to draw oxygen directly from the air.
Locomotion on Land: A few fish use powerful body undulations, fin extensions, or even a “soldier crawl” to move overland in search of new habitats or to escape predators.
Desiccation Resistance: Behavioral strategies like burying themselves in mud, seeking shade, or hiding in moist crevices help retain body moisture during overland journeys.

For these fish, walking on land or taking shelter above ground can mean the difference between life and death in the face of drought, pollution, or predation.

Notorious Land-Walking Invasive Fish

While land-walking is rare, several invasive species have mastered this skill, often to the dismay of native wildlife and local ecosystems. Here are some infamous examples:

Northern Snakehead (Channa argus)

Originally from Asia, the northern snakehead boasts a reputation as a voracious and adaptable invader. First discovered in the United States in 2002, this species can grow quite large—over 19 pounds—and is now established across the Potomac River system, with sightings reported as far as Massachusetts and California.

Adaptation: Utilizes a “soldier crawl”—bracing with its tail and head to move slowly over land.
Duration on Land: Survives days out of water by breathing air directly.
Drivers for Land Travel: Primarily high salinity, low pH, or high CO2—conditions more common in its native Asian habitats than in North America.
Impact: Threatens native fish populations in invaded territory and is considered ecologically disruptive.

Climbing Perch (Anabas testudineus)

Despite its name and legendary reputation, the climbing perch does not truly climb trees, but its terrestrial exploits are impressive. Originating across South and Southeast Asia, it has become invasive in Australia.

Adaptation: Possesses a labyrinth organ for air breathing and can walk on land for several hundred meters.
Duration on Land: Survives 6–10 hours, even longer by burying itself in mud during droughts.
Unusual Predator Prey Interaction: Its spiny fins sometimes kill birds that attempt to swallow it.
Mythbusting: The famous tales of climbing perch scaling tree trunks appear to be folklore, though the species is adept at navigating moist logs and debris.

Walking Catfish (Clarias batrachus)

The walking catfish is native to Southeast Asia but now proliferates in Florida’s waterways, often encountered in unlikely places including urban parking lots.

Adaptation: Uses body undulations and pectoral fins to traverse land.
Duration on Land: Survives up to 18 hours out of water and can travel over three-quarters of a mile, especially during rainy conditions.
Ecological Role: Although initially feared, their true threat is considered minor; they are largely a nuisance.
Legal Status: Illegal to possess or transport live walking catfish in Florida; environmental sensitivity to cold limits further spread.

Mangrove Killifish (Kryptolebias marmoratus)

Undoubtedly the most remarkable of the bunch, the mangrove killifish demonstrates both terrestrial and arboreal specialization.

Habitat: Resides in tidal mangrove forests, ranging from Florida to Brazil.
Adaptation: During dry periods, it climbs into rotting logs and tree crevices, where its physiology switches from gill-based respiration to absorbing oxygen and excreting waste through the skin.
Duration without Water: Can survive over two months out of the water, essentially “waiting out” droughts high above the ground.
Behavioral Shift: Becomes less territorial during these periods, prioritizing survival over aggression.

Fish That Scale Trees: Fact Versus Fiction

Legends have long inspired an exaggerated vision of fish climbing into forest canopies. While stories about climbing perch scaling tall trees are widespread, scientific evidence supports a more grounded view:

Species	True Tree Climbing?	Notes
Climbing Perch	No (walks on land, climbs logs/debris but not trees)	Misinterpreted folklore; adept at traversing obstacles
Mangrove Killifish	Partially (shelters in tree crevices, not branches)	Remarkable survival strategy in humid forests
Northern Snakehead	No	Land walker but not a climber
Walking Catfish	No	Overland travel only

Although none truly perch among branches, these abilities challenge our understanding of aquatic life and hint at the evolutionary steps that bridged water and land for vertebrates.

Ecological Impact of Land-Walking Fish

While these fish may inspire admiration for their resilience, their presence—especially in non-native regions—carries profound consequences:

Predation on Natives: Snakeheads and walking catfish can outcompete or prey upon indigenous species, threatening ecosystem stability.
Habitat Disturbance: These fish can rapidly colonize new habitats, using land travel to invade isolated ponds, wetlands, or floodplains that would otherwise be protected from aquatic invaders.
Unintentional Killers: Climbing perch can kill native birds such as herons or cormorants that attempt to eat them, due to their spiny fins.
Disease Transmission: Invasive fish can introduce new parasites or diseases to native populations.

Humans, Ecology, and the Spread of Invasive Fish

Human activity is the main culprit behind the spread of these amphibious invaders. Whether intentional (via exotic pets, food trade) or accidental (from aquaculture escapes or bait releases), fish that can travel overland can quickly turn a localized introduction into a far-reaching invasion.

In some regions, regulations require anglers to immediately kill species like the northern snakehead or walking catfish, and make it illegal to possess or transport them alive. However, detection and eradication can be extremely challenging, as these fish evade traditional barriers by simply taking to land or exploiting drainage infrastructure during storms.

Climate change may also facilitate the range expansion of land-walking fish, as droughts, floods, and habitat changes make survival skills like air-breathing and terrestrial locomotion more advantageous than ever.

The Symbolism and Evolutionary Significance

Beyond their nuisance or threat, the ability of a fish to walk on land or climb into a log is a living reminder of our evolutionary past. The transition from aquatic to terrestrial life was shaped by similar adaptations—breathing air, resisting desiccation, and overcoming gravity’s pull. Some scientists speculate that early vertebrates may have used the roots or lower trunks of primitive trees as transitional spaces as they slowly adapted to life on land.

These remarkable fish blur the boundaries between old evolutionary epochs and the modern world—a testament to adaptability and the relentless drive for survival.

Frequently Asked Questions (FAQs)

Q: Can all land-walking fish climb trees?

A: No. Only a handful can physically leave water, and of these, none truly climb high among tree branches. Some, like mangrove killifish, take refuge in crevices of logs or trees, but vertical climbing capabilities are very limited.

Q: Why do snakeheads, walking catfish, or climbing perch walk on land?

A: They do so mainly to escape poor environmental conditions, such as low oxygen or drying water, and to find new habitats or avoid predators. Their overland journeys are typically short and focused on survival rather than exploration.

Q: Are land-walking fish dangerous to humans?

A: Most are not dangerous to people, but they can disrupt native wildlife dramatically, outcompete local fish, threaten aquatic birds, and carry diseases.

Q: What can be done to prevent the spread of invasive land-walking fish?

A: Adhering to local regulations (such as immediate killing and disposal), never releasing aquarium or bait fish, reporting sightings, and maintaining physical barriers in waterways can collectively help limit their spread.

Q: How do these fish breathe when out of water?

A: Adaptations vary: labyrinth organs, modified gills, or, in the case of mangrove killifish, even their skin, allow oxygen absorption from the air, enabling days or months of survival outside water.

Key Takeaways

Some invasive fish—like northern snakehead, walking catfish, climbing perch, and mangrove killifish—have evolved to survive and travel on land using unique respiratory and locomotive adaptations.
Stories of fish climbing trees are mostly exaggerations, although some species do climb over logs or shelter in rotting wood during droughts.
These remarkable survival techniques enable them to expand into new habitats, where they can threaten native species, disrupt ecological balance, and challenge traditional barriers.
Efforts to manage these invaders require strict policy enforcement, public awareness, and preventive measures to reduce human-facilitated spread.

References

Author

medha deb

Medha Deb is an editor with a master's degree in Applied Linguistics from the University of Hyderabad. She believes that her qualification has helped her develop a deep understanding of language and its application in various contexts.

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