AT A GLANCE
- Common Name: Climbing Perch
- Scientific Name: Anabas testudineus
- Category: Fish
- Subcategory: Bony Fishes
- Range: South and Southeast Asia, widespread from India, Pakistan, and Sri Lanka east through Myanmar, Thailand, Malaysia, Indonesia, and southern China
- Habitat Type: Lowland freshwater rivers, slow-moving streams, canals, flooded rice paddies, stagnant swamps, and seasonal pools with heavy aquatic vegetation
- IUCN Red List Status: Least Concern
- Lifespan: 5 to 8 years
- Diet: Carnivorous/Omnivorous (aquatic insects, larvae, small crustaceans, worms, small fish, mollusks, alongside decaying plant matter)
- Average Size/Weight: Total length 15 to 25 cm; weight 100 to 250 g
- Key Defining Feature: Armored, hardy freshwater fish equipped with a complex labyrinth organ allowing it to breathe atmospheric air and spiny gill plates that enable it to crawl across dry land
Overview
The Climbing Perch (Anabas testudineus) is an extraordinary, amphibious freshwater fish celebrated throughout Asia for its legendary hardiness and ability to travel overland. Belonging to the labyrinth fish family Anabantidae, this armored survivor possesses a specialized auxiliary respiratory labyrinth organ located in its head, which enables it to breathe atmospheric oxygen directly from the air. When drought strikes or seasonal pools dry up, the Climbing Perch simply crawls out of the mud and walks across dry land in search of deeper water.
Biology and Physical Characteristics
Anabas testudineus has an oblong, robust, slightly compressed body covered in tough, hard ctenoid scales colored dark brownish-grey to olive-green with a pale yellowish abdomen. The margins of its operculum (gill cover) are armed with sharp, backward-pointing serrations and spines. Above its gills lies the labyrinth organ—a highly folded, vascularized suprabranchial organ derived from the first gill arch that absorbs oxygen directly from ingested air. So dependent is this fish on air that it is an obligate air breather; if denied access to the water surface, it will paradoxically drown.
Behavior and Ecology
When aquatic conditions deteriorate due to drought, oxygen depletion, or seasonal evaporation, the Climbing Perch initiates terrestrial locomotion. Flaunting its spiny gill covers, it digs the backward-facing opercular spines into the soil while using its muscular pectoral fins and thrashing tail to haul its body forward across grass, mud, and roads, traveling hundreds of meters between water bodies during damp nights. During severe dry seasons, it can burrow deep into damp subterranean mud, entering a state of torpor (aestivation) for weeks until the monsoon rains return.
Conservation and Human Impact
The Climbing Perch is assessed as Least Concern on the IUCN Red List. It is an exceptionally adaptable, prolific, and abundant species across its native South and Southeast Asian range. It forms an important staple food source in rural aquaculture and freshwater artisanal fisheries, renowned for staying alive for days out of water if kept damp.
Interesting Factoid
The Climbing Perch can walk across dry land using its spiny gill covers like crutches, and early explorers actually found them up in palmyra palm trees after birds had dropped them there, leading to the legend that the fish climbed trees.