Taxonomy & naming
Nanobagrus immaculatus was described by Heok Hee Ng in 2008 and is valid in the Catalog of Fishes. It belongs to the Bagridae, and Nanobagrus is a genus of miniature Southeast Asian bagrids. Wet Spot has sold it under its scientific name.
Morphology
FishBase gives a maximum length of 1 in SL for males or unsexed fish. That makes it a true dwarf in a family best known for large predatory catfishes. The epithet immaculatus, meaning unspotted, points to a plain colour pattern.
Habitat
FishBase records the species from the Kahayan River drainage of southern Borneo, Indonesia, as a freshwater, demersal, tropical fish. The type locality is a backwater stream northwest of Palangkaraya in Kalimantan Tengah. No temperature, pH or hardness figures are recorded.
Feeding
No diet is recorded for this species. Dwarf bagrids generally feed on small invertebrates taken near the bottom, but no observation exists for N. immaculatus.
Mating
Courtship has not been described.
Breeding
No spawning or egg information is recorded, and aquarium breeding is not documented.
In the aquarium
At under 1 in SL it needs a small, calm tank with leaf litter, wood and dim light, and tankmates small and peaceful enough not to harass it. Offer tiny live and frozen foods in the evening. No water-chemistry targets are published for it.
Conservation
IUCN lists Nanobagrus immaculatus as Vulnerable. It is known from a single drainage in southern Borneo, where lowland stream habitat is under pressure from land clearing and drainage.