Climbing perch
Anabas testudineus
Also known asKoi (Bengali) · Thai koi
Water parameters
Minimum tank: 150 L per individual at harvest size.
Feed and growth
- Feed protein
- 35% target
- Daily feed (warm)
- 2.00% of body weight
- Daily feed (cool)
- 0.50% of body weight
- Max density
- 50 g per litre
A 250 g adult eats about 5.0 g of feed per day at optimum. 10 fish at adult size: ~50 g daily.
Legality
Rules vary by jurisdiction and change over time. Verify with your local fisheries or wildlife authority before stocking.
| Jurisdiction | Status | Notes |
|---|---|---|
| United States (federal) | prohibited | Lacey Act injurious species under "walking perch" listing verified 2026-05-13 |
| California | prohibited | verified 2026-05-13 |
| Florida | prohibited | verified 2026-05-13 |
| New South Wales | prohibited | Established invasive in Torres Strait Islands; mainland eradication priority verified 2026-05-13 |
| Queensland | prohibited | verified 2026-05-13 |
| European Union (bloc) | prohibited | EU Union List of Invasive Alien Species verified 2026-05-13 |
Unlisted jurisdictions default to "check local regulations".
Origin and habitat
Anabas testudineus is an air-breathing freshwater fish of the family Anabantidae, native across South and Southeast Asia from Pakistan, India, Sri Lanka, and Bangladesh east to southern China and through Southeast Asia west of the Wallace Line. It carries a labyrinth organ above the gills, the largest relative to body size of any anabantid, which lets it pull oxygen from air and survive in near-anoxic water, in mud during dry spells, and out of water for a time if kept damp. It is famous for moving overland between pools, usually at night, levering itself along on stout spines of the gill covers and its pectoral fins, sometimes for hundreds of metres. That hardiness and mobility make it both a resilient culture fish and a difficult invader to contain. It reaches about 25 cm and a few hundred grams. A common food fish in rural South and Southeast Asia, caught wild or grown in extensive ponds, it has white, rather bony flesh that is widely eaten across the region.
Climate and outdoor ponds
- Climate
- tropical (needs warm water year-round)
- USDA zones
- 10–13 (winter low around -1°C or warmer)
- Heating needed
- yes
- Cooling needed
- no
Care notes
A tropical, low-input species well matched to warm Southeast Asian aquaponics. It does best around 28–30°C within a working range of roughly 22–35°C, and it thrives in the warm, nutrient-rich water typical of tropical systems. Growth is moderate, around 100–200 g in eight to twelve months on a pellet of 28 to 35 percent protein, with feed conversion roughly 1.5 to 2.5. Its extreme tolerance is the selling point: because it breathes air, it shrugs off near-zero dissolved oxygen, wide pH swings, high ammonia, and brief dewatering, which makes it close to foolproof for beginners in the tropics, and it takes crowding well, so stocking can run high. The catch is containment and legality. Climbing perch is a declared noxious species in Queensland, has invaded islands of the Torres Strait, and is listed as a prohibited invasive in the European Union and barred in several US jurisdictions; its air-breathing and overland travel make escapes hard to prevent, so any escape into warm local waters risks a new invasive population. Where it is legal and traditional, mainly South and Southeast Asia, it is a practical, durable fish for low-tech aquaponics.