Taxonomy & naming
Ompok binotatus was described by Heok Hee Ng in 2002. It belongs to the family Siluridae, the Old World sheatfishes and glass catfishes, a group whose classification has been repeatedly revised as species once lumped under broader genera such as Silurus were split out into Ompok, Kryptopterus, Wallago and others. The Catalog of Fishes treats Ompok binotatus as the currently valid name; there is no indication in available sources that it has ever carried a different combination.
The genus name Ompok is a Sundanese vernacular name for sheatfishes of this type, long used in Indonesian and Malay fish literature before being adopted as the formal genus. The species epithet binotatus is Latin, built from bi- ("twice" or "two") and notatus ("marked"), referring to the pair of dark spots on the humeral region and at the base of the caudal peduncle that distinguish this species from its congeners.
Morphology
Ompok binotatus has the typical sheatfish silhouette shared across the genus: a long, laterally compressed, scaleless body, a flattened head, a long anal fin running much of the body's length, and a small, low dorsal fin set well forward. The diagnostic feature is the pair of dark spots referenced in its name — one at the humeral (shoulder) region behind the head, the other at the base of the caudal fin — set against an otherwise silvery to pale body typical of Siluridae.
Published data on this species' own size is sparse; no confirmed maximum length figure for O. binotatus specifically was found in available sources. This matters because the genus as a whole is a genuine size trap: related species such as O. bimaculatus and O. pabda are documented in the 6–17.5 in range, with Ompok in general reaching 15.5–17.5 in maximum. Given its placement in the same genus, O. binotatus should be assumed capable of substantial growth rather than assumed to stay small, until better data is published. As in all Siluridae, the skin is naked — no scales — which has direct consequences for how the fish should be medicated (see "In the aquarium").
Habitat
Ompok binotatus is known only from the Kapuas River system in Kalimantan Barat (West Kalimantan), western Borneo — the type locality is Sungai Mandai Kechil near its confluence with the main Kapuas channel, about 11 mi west-southwest of Putussibau. The Kapuas is the longest river in Indonesia and its freshwater ecoregion is exceptionally diverse, home to roughly 300 fish species, around 68 of them endemic to the system.
The Kapuas basin is characterised by very soft, acidic blackwater habitat in many of its reaches — tea-stained by dissolved tannins from surrounding peat and forest — though as a large river system it also includes clearer, more mineral reaches. Specific temperature and pH figures for O. binotatus have not been documented in available sources; it should be treated as a warm, soft-to-acidic tropical Southeast Asian river fish typical of the Kapuas system rather than assigned invented numbers.
Feeding
No species-specific dietary study of Ompok binotatus was found in available sources. Sheatfish catfishes in the genus Ompok are generally nocturnal predators that take fish, aquatic invertebrates and other prey they can swallow whole, foraging along the riverbed and among cover after dark, in keeping with the broader predatory habits of Siluridae.
In the absence of species-specific feeding data, keepers and researchers should default to the genus pattern: a piscivorous predator that will take any tankmate small enough to swallow, alongside meaty foods such as whole fish, prawn and large sinking pellets. Given how little is documented for this species, this should be treated as an inference from its relatives rather than a confirmed account of its diet.
Mating
Nothing specific has been published on the courtship or spawning behaviour of Ompok binotatus. Among the Siluridae, glass catfishes of the genus Kryptopterus are essentially never bred in captivity and the aquarium trade in that group relies entirely on wild-caught fish. The larger river-dwelling sheatfishes — Ompok, Wallago, Silurus — are understood to be river spawners in the wild, and where they are produced at all for trade or restocking it is typically through farm propagation rather than natural pairing in a home tank.
For O. binotatus specifically there is no documented account of wild spawning behaviour, courtship, or triggers, and none should be assumed. Given the total absence of trade or hobbyist interest in this species, no reproductive behaviour can be described with any confidence.
Breeding
There is no record of Ompok binotatus being bred in captivity. It is not established in the aquarium hobby at all — it lacks even a hobbyist profile on species-tracking sites — so there is no home-aquarium breeding account to draw on, unlike the handful of Siluridae, such as some Kryptopterus and Ompok species, that occasionally reach the trade as wild imports.
The honest position, consistent with its larger congeners, is that any commercial-scale propagation of river sheatfishes in this genus is done through farming or hormone induction for food-fish purposes rather than aquarium breeding, and that O. binotatus itself has no documented breeding record of any kind, wild or captive. Keepers should not expect to breed this species and should assume any specimen encountered is wild-collected.
In the aquarium
Ompok binotatus is not established in the aquarium trade — it has no dedicated profile on hobbyist reference sites and appears to be effectively unknown outside the taxonomic literature describing it. Anyone who does encounter this species, whether as a genuine import or a misidentified congener, should treat it with the same caution warranted by its size-trap genus: related Ompok reach 15.5–17.5 in, and nothing published rules out this species reaching a comparable size, so it should not be assumed to stay small or be housed in a standard home tank.
As a scaleless silurid, it is medication-sensitive in the same way as loaches, puffers and other naked-skinned catfishes — copper-based treatments and many standard medications should be dosed conservatively, often at half strength. Sheatfish catfishes generally carry stiff spines that can lock and tangle in a net, so any handling should use a container rather than a net where possible. Given its predatory habits (inferred from the genus) it should only be kept with tankmates too large to be swallowed, and given its likely nocturnal habits it should be provided with dark cover for daytime retreat. Because almost nothing is documented about this species' actual husbandry requirements, anyone keeping it should treat this as a poorly known fish and err on the side of a large, understated setup rather than a small showcase tank.
Conservation
Ompok binotatus has not been evaluated by the IUCN Red List; its status is Not Evaluated. It is known only from the Kapuas River system of western Borneo, a single-river endemic in a basin that itself holds around 68 endemic fish species out of roughly 300 total — a pattern typical of many narrow-range Southeast Asian catfishes that have simply never been assessed.
The Kapuas basin faces ongoing pressure from deforestation, peatland conversion, mining and general land-use change across Kalimantan, all of which affect water quality and habitat in ways that could plausibly affect a narrow-range endemic like this species, even though no population trend or threat analysis specific to O. binotatus has been published. Its absence from the aquarium trade means collection pressure is not a relevant concern for this species, in contrast to more heavily traded Southeast Asian catfishes.