Green Catfish

Hemibagrus nemurus is one of the most widespread and commonly encountered large bagrid catfish in Southeast Asia, inhabiting lowland rivers, floodplains, and reservoirs from Thailand through the Malay Peninsula to Indonesia. Its olive-brown colouration, long flattened head, and powerful, muscular body make it unmistakable. In the wild it is primarily nocturnal, spending days sheltering under submerged logs and rocks before emerging to hunt fish and large invertebrates after dark.

In the aquarium, H. nemurus is significantly more manageable than its giant relative H. wyckioides, topping out around 65 cm in captivity. It requires a large tank with good filtration and places to retreat during daylight hours. It is most active after lights-out and will reliably come forward at feeding time once settled. Juveniles can be quarrelsome with conspecifics so should be housed separately.

This species adapts well to a range of large carnivore foods — fresh fish portions, prawns, earthworms, and good-quality large pellets are all accepted. It is a solid choice for keepers who want a substantial, characterful predatory catfish without committing to the extreme scale required for the very largest species.

Water: 22–28°C, pH 6.0–7.5, moderate flow; strong canister or sump filtration recommended. Tank: 1 000 L minimum; large PVC pipe or slate cave hides; dim lighting. Feeding: Fish portions, large prawns, earthworms, large pellets; feed every 2–3 days. Breeding: Rare in captivity; pit-spawning behaviour reported; parental care by male. Compatibility: Will eat fish that fit in its mouth; best with similarly sized robust species.