Climbing Perch

The climbing perch is one of the most air-tolerant freshwater fish in the world, native to a broad swath of South and Southeast Asia from India to the Philippines. Its common name comes from historical accounts, since embellished, of the fish 'climbing' trees; in reality it uses its spiny gill covers and muscular body to haul itself short distances overland, particularly during rains, in search of new water. This ability lets it colonize temporary ponds, rice paddies, and puddles that dry seasonally. Equipped with a labyrinth organ, it can survive out of water for extended periods as long as its gills stay moist, making it one of the hardiest fish in its range.

• Robust, elongated body with large, coarse ctenoid scales
• Olive-green to brownish-gray coloration, often with a dark spot near the base of the tail and gill cover
• Serrated, spine-edged gill covers (opercula) used for overland movement
• Broad, somewhat flattened head with small eyes set high
• Continuous, spiny-rayed dorsal fin running most of the back length
• Distinguished from true perches by its labyrinth organ and lack of a separate spiny/soft dorsal fin division
• Pectoral fins used in a rowing motion to drag itself across wet ground

Climbing perch occur throughout freshwater lowlands of South and Southeast Asia, from India and Sri Lanka east through Myanmar, Thailand, Indochina, and the Philippines, with introduced populations elsewhere. They inhabit ponds, swamps, ditches, canals, flooded rice fields, and slow, weedy streams, often in shallow, warm, oxygen-poor water. Their labyrinth organ allows survival in stagnant or seasonally drying habitats where most fish would suffocate, and they can persist buried in mud during droughts. During heavy rains they may move overland between isolated water bodies. This tolerance for poor water quality and temporary habitats has also made them a successful, sometimes invasive, species outside their native range.

Climbing perch are opportunistic omnivores, feeding on insects, worms, small crustaceans, other fish, and plant material as available. They are solitary and often aggressive toward other fish, using their spiny gill covers defensively when threatened or handled. Their most distinctive behavior is overland travel: using rigid pectoral fins and a side-to-side wriggling motion aided by the spiny opercula, they can move across wet ground for short distances to reach new water, especially after rain. They breathe air directly via the labyrinth organ, letting them survive prolonged periods out of water or buried in damp mud during dry spells. Spawning occurs in flooded vegetation, with eggs scattered and left unguarded.