The walking catfish (Clarias batrachus) is a species of freshwater airbreathing catfish native to Southeast Asia. It is named for its ability to "walk" and wiggle across dry land, to find food or suitable environments. While it does not truly walk as most bipeds or quadrupeds do, it can use its pectoral fins to keep it upright as it makes a wiggling motion with snakelike movements to traverse land. This fish normally lives in slow-moving and often stagnant waters in ponds, swamps, streams, and rivers, as well as in flooded rice paddies, or temporary pools that may dry up. When this happens, its "walking" skill allows the fish to move to other aquatic environments. Considerable taxonomic confusion surrounds this species and it has frequently been confused with other close relatives. One main distinction between the walking catfish and the native North American ictalurid catfish with which it sometimes is confused, is that the walking catfish lacks an adipose fin. It can survive 18 hours out of water.
The walking catfish is a tropical species native to maritime Southeast Asia. The native range of true Clarias batrachus is confirmed only from the Indonesian island of Java, but three closely related and more widespread species frequently have often been confused with this species. These are C. magur of northeast India and Bangladesh, a likely undescribed species from Indochina, and another likely undescribed species from the Thai-Malay Peninsula, Sumatra, and Borneo. Both of these undescribed species have been referred to as, Clarias aff. batrachus. At present, the taxonomic position of the Philippines population (called hito or simply "catfish" by the locals) is unclear, and it also is unclear whether South Indian populations are C. magur or another species. As a consequence, much information (behavioral, ecological, related to introduced populations, etc.) listed for C. batrachus, may be for the closely related species that have been confused with true C. batrachus. True C. batrachus, C. magur and the two likely undescribed species are all kept in aquaculture.
Walking catfish thrive in stagnant, frequently hypoxic waters, and often are found in muddy ponds, canals, ditches, and similar habitats. The species spends most of its time on, or right above, the bottom, with occasional trips to the surface to gulp air.
In the wild, this creature is omnivorous; it feeds on smaller fish, molluscs, and other invertebrates, as well as detritus and aquatic weeds. It is a voracious eater that consumes food supplies rapidly, so it is considered harmful when invasive.
A white variation with black patterns is commonly seen in the aquarium fish trade. However, this color variation also is prohibited where walking catfish are banned. Very well-rooted plants and large structures that provide some shade should be included in an aquarium with these fish. Any small tankmates will be eaten by this fish.
