Taxonomy & naming
Gray described the species in 1835, from a specimen with no locality, and the Catalog of Fishes records that the specimen did not come from India. It is now placed in Nandus, a genus of Asian leaffishes of the family Nandidae. The common name Bornean leaffish comes from FishBase.
Morphology
A laterally compressed ambush predator with a large, protrusible mouth and mottled brown colouring that resembles a dead leaf. FishBase notes that the species is solitary and strongly resembles a piece of dead leaf. It reaches 4.5 in TL.
Habitat
FishBase records the species from hill streams to peat swamps and from small streams and flooded forest, in fresh and brackish water. The range runs from Thailand to Indonesia. FishBase gives a temperature range of 22 to 26 C.
Feeding
The species feeds on small fishes and crustaceans (FishBase). In aquaria it needs live prey, such as feeder shrimp, small livebearers and similar fish, and many learn to take frozen foods.
Mating
Courtship and spawning behaviour are not described for this species in the sources available to the atlas.
Breeding
Eggs, larvae and clutch size are not recorded by FishBase, and the species is not known to be regularly bred in aquaria.
In the aquarium
Keep it alone or with fish too large to swallow, in a tank with leaf litter, wood and dim lighting. It waits motionless for prey, so tank mates need to be too big for its mouth, which opens wider than the body suggests. Soft, slightly acid and warm water, in the 22 to 26 C that FishBase gives, suits it.
Conservation
The IUCN Red List classes Nandus nebulosus as Least Concern, last assessed in June 2019.