The walking catfish (Clarias batrachus) is a freshwater fish native to Southeast Asia, recognized for its unique ability to move across land. This species is found in various aquatic environments, including slow-moving streams, ponds, swamps, and even flooded rice paddies. Its widespread distribution and distinctive terrestrial locomotion make it a subject of interest.
Foods in Their Natural Habitat
The walking catfish is an omnivorous and scavenging species. As larvae, they primarily feed on plankton before transitioning to larger organisms as fry. Juveniles predominantly consume insects. Adult walking catfish exhibit a diverse diet, including aquatic plants such as benthic algae, and a variety of invertebrates like insects, crustaceans, and mollusks.
They also prey on smaller fish, fish eggs, and larvae of other species. Beyond live prey, walking catfish readily consume detritus and carrion. This adaptability to different food sources contributes to their success in various environments, including areas where they have been introduced as an invasive species.
Opportunistic Feeding Behavior
Walking catfish acquire food through opportunistic behaviors. They are primarily nocturnal, using their sensory barbels to locate food in murky waters and low-light conditions. These fish actively sift through the bottom substrate, including detritus and soft mud, in their search for sustenance.
Their feeding habits are not restricted to aquatic environments; walking catfish are known to forage on land. This ability allows them to exploit terrestrial prey, such as earthworms and other invertebrates, although they require water to swallow. Their indiscriminate feeding, where they consume almost anything available, is a significant factor in their ability to thrive and, in some cases, outcompete native species.
Dietary Adaptations and Versatility
The walking catfish possesses several physical and physiological adaptations that enable its diverse diet. Their broad mouth and bristly teeth allow them to consume a wide range of food sizes and types. Four pairs of well-developed barbels surrounding their mouth function as sensory organs, helping them navigate their surroundings and detect food in dark or turbid waters.
A distinct adaptation is their accessory air-breathing organ. This organ allows them to breathe atmospheric air, enabling survival in low-oxygen aquatic environments or out of water for extended periods, sometimes up to 18 hours. This air-breathing capability, combined with their ability to “walk” or wiggle across land using their pectoral fins, allows them to move to new food sources when their current habitat becomes unfavorable or dries up.