The scientific name of the walking catfish is Clarias batrachus. Clarias comes from the Greek word Chlaros, which means “vigorous”. As the name suggests, the fish can move outside the water on the land by wiggling its body back and forth.
Join us as we delve into its appearance, size, diet, and other facts of the fascinating world of the walking catfish, a unique species known for its remarkable land-walking abilities and intriguing mating behavior.
Appearance
The walking catfish has a long, eel-like body and scale-free skin. It is brownish-gray with many tiny white spots along its lateral line. The head is flat and wide, and the body narrows towards the tail in a way reminiscent of a tadpole. Although the gape is small, the mouth can open wide. The four pairs of barbels emerging from the massive mouth region are perhaps the most noticeable feature. These barbels function as sensors, monitoring their surroundings and looking for prey.
Depending on their environment, the walking catfish grows between 8 and 47 cm (3 to 18.5 inches) long and can weigh up to 1.2 kilograms (2.6 pounds). The largest record for this species is 61 cm (24 inches) in its native region, while the longest specimens in South Florida seldom surpass 36 cm (14 inches).
Their lifespan remains yet to be determined, but with some research on closely similar species, it has been estimated that they can live between 15 to 16 years in captivity.
How Does It Walk?
Each pectoral fin of the Walking Catfish has a strong, bony spine at the front. These spines are essential for the walking movement. The catfish anchors itself by inserting the spines of its pectoral fins into the ground. This provides a stable point from which to push off. Then, it flexes its body in a wave-like motion. This flexing is similar to the motion used by snakes, allowing the fish to propel itself forward.
The adaptation benefits of the walking catfish’s remarkable abilities include:
- Survival in Low Water: This walking ability allows the Walking Catfish to survive in environments where water bodies may dry up or become hypoxic. It can travel to new water sources, increasing its chances of survival.
- Predator Avoidance: Being able to move on land helps the Walking Catfish escape from aquatic predators and search for food in new areas, giving it a significant advantage in its native and introduced habitats.
Habitat
Walking catfish are endemic to Southeast Asia where they may be found in abundance in freshwater and brackish water bodies such as rivers, lakes, wetlands, and rice paddies.
Its native range includes Pakistan, Sri Lanka, Singapore, Malaysia, Bangladesh, India, Indonesia, Myanmar, Laos and Thailand.
However, it now has a global distribution following introductions for cultivation purposes.
Walking catfish are most recognized for their capacity to live in places where other fish cannot. This fish prefers warm, stagnant, frequently hypoxic waters such as ponds, canals, swamps, and flooded plains often with poor water quality. Except for brief excursions to the surface for gulps of atmospheric air, this species spends most of its life on or near the substrate.
Invasion of Non-Native Habitats
Due to its resilience in new habitats, the dispersal of the walking catfish globally has become an issue. Beyond its native habitat, it is recognized as a significant pest, capable of causing considerable ecological and economic damage. As a result, many countries have banned the species. In the United States, for example, all members of the family Clariidae, including the Walking Catfish, are classified as injurious wildlife and are illegal to possess without a federal permit.
Diet & Feeding Habits
The walking catfish is a benthic omnivore that diligently forages for its food. Active during the night, it uses its barbels to scour the bottom, vigorously sifting through debris and soft substrates.
As a true generalist, this species has a diverse diet which includes benthic algae, the larvae of other fish, small fish, and a variety of invertebrates like annelids, shrimp, crustaceans and insects. It is also a detritivore, feeding on detritus (decomposing organic matter).
The walking catfish changes throughout its development. As larvae, they are exclusively planktonic feeders. During the fry stage, they transition to hunting larger organisms. Finally, juveniles become primarily insectivorous.
Reproduction
These fish mate during the monsoon season, which lasts from June to August. Walking catfish are monogamous and when two fish form a couple, they will seek out a cave or dense vegetation where they may dig a hole to create nests.
One of the most remarkable aspects of the walking catfish is its mating behavior, which occurs in phases:
During the initial stage, the male will swim in multiple loops around the female until his body is entirely wrapped around hers. As the mates get to know one other, the initial spawning will produce only a few eggs.
During successive spawning cycles, the female will begin to produce more and more eggs.
On average, this process takes around 20 hours and yields 8,000 bright orange eggs. Even after the eggs hatch, the mother and father continue to provide parental care by guarding the fry from predators during the first 24 hours. By the end of the third day, the sac fry should know how to swim and be functionally independent.
Threats
The conservation status of the walking catfish is “Least Concern”. However, it has become vulnerable due to habitat loss from droughts and human activities in countries like Malaysia and India.
Additionally, competition from the larger African catfish has significantly reduced its population. To combat this decline, conservationists in Asia are employing methods like induced spawning and artificial breeding to bolster wild populations.
5 Facts About the Walking Catfish
- Outside its native range, the walking catfish is a highly invasive species.
- The walking catfish carries several internal parasites, including tapeworms and trematodes.
- While brown-gray is the most common coloration, captive-bred walking catfishes can also be albino, mottled or piebald.
- A walking catfish has 27,000 taste buds and uses its entire body to smell food.
- The walking catfish uses its lateral line to act like a sixth sense, feeling vibrations in the water to navigate and sense its surroundings.
FAQs
Do walking catfish breathe air?
Walking Catfish have specially adapted gills that contain intricate, tree-like structures allowing it to breathe air directly. This is a vital adaptation for surviving in stagnant water and even venturing onto land for short periods.
How did the walking catfish get to Florida?
In the early 1960s, the walking catfish arrived in Broward County, Florida through two main routes: the aquarium trade and accidental releases. Ironically, after Florida banned their import and possession in 1967, fish farmers in possession released them intentionally in 1967 and 1968. By the 1970s, the walking catfish had established themselves in over 20 Florida counties, and their range has continued to expand into other states.
How long can a walking catfish stay on land?
The walking catfish can travel up to 1.2 kilometers on land and live for up to 18 hours outside water or as long as their gills remain moist. They can tolerate temperatures of 0 to 18 degrees Celcius (32 – 64.4 degrees Fahrenheit).
How do walking catfish walk on land?
The walking catfish uses its unique anatomy for land travel. Each pectoral fin boasts a strong, bony spine at its front, acting like a tiny anchor. By propelling itself forward with these spines and flexing its body in a wave-like motion, the catfish achieves a remarkable “walking” movement on land.
Do walking catfish have predators?
The walking catfish face a variety of predators, including otters, large reptiles like crocodiles, and fish-eating birds like eagles. Their most unique defense is their sharp, venomous, dagger-like spines located near their dorsal fins.
