Taxonomy & naming
Ompok platyrhynchus was described by Heok Hee Ng and Heok Hui Tan in 2004, in Zootaxa, from material collected in the Temburong River drainage of Brunei Darussalam, on the northern coast of Borneo. It belongs to the family Siluridae — the sheatfishes and glass catfishes of Europe, Africa and Asia — and to the genus Ompok, a group of small to medium Asian river catfishes that also includes food and aquarium species such as O. bimaculatus.
The genus Ompok has been shuffled repeatedly across Siluridae as the family has been revised; older literature and some databases may still list related species under Silurus or other historical combinations, but the Catalog of Fishes treats Ompok as the valid genus for this species. The epithet platyrhynchus is descriptive of the fish's head shape (see Etymology). No synonyms are documented in the sources consulted; the species has not been the subject of a taxonomic revision since its description.
Morphology
This is a small, slender-bodied siluriform reaching only about 3 in standard length, among the smallest members of its genus. The original description notes a comparatively short snout, a relatively slender body, and the absence of a distinct nuchal (neck) concavity that separates the head profile from other Ompok. The anal fin is long, with 74–80 rays running most of the length of the underside — a classic sheatfish trait — and the vertebral count is high for the genus, at 59–60.
Like all Siluridae, O. platyrhynchus is scaleless, with smooth, naked skin rather than the bony plating seen in armoured catfish families; this has direct consequences for medicating the species (see "In the aquarium"). A single pair of long maxillary barbels reaches back to about the middle of the pectoral fin, used for tactile and chemosensory foraging along the streambed. No colour pattern is recorded in the sources available.
Habitat
Ompok platyrhynchus is known only from the Temburong River drainage in Brunei Darussalam, in the far north of Borneo — a small, clear, fast-flowing meandering stream running over rock and sand substrate. This is a headwater/upland stream habitat rather than the slow, silty lowland rivers many larger Siluridae favour, and it points to a fish adapted to well-oxygenated, moving water rather than still ponds.
No detailed water chemistry has been published for the type locality in the sources reviewed here. Borneo's clearwater streams are typically soft and mildly acidic to circumneutral, but that should be read as a general regional expectation rather than a measured value for this species specifically — treat any precise pH/hardness figures for O. platyrhynchus as unconfirmed until better data surfaces.
Feeding
No feeding studies have been published for this species. Based on its build — a small-mouthed, barbelled sheatfish from fast-flowing rocky streams — it is reasonable to infer a diet of small aquatic invertebrates (insect larvae, small crustaceans) picked from the substrate and drift, in line with other small stream-dwelling Siluridae. This inference is not confirmed by direct observation and should be treated as provisional.
Given the uncertainty, anyone encountering this species (almost certainly only in a research or museum context, not the aquarium trade) should offer small live or frozen invertebrate foods rather than assuming it is a piscivore on the scale of its larger relatives like Wallago.
Mating
Nothing has been published on the reproductive behaviour of Ompok platyrhynchus. Among Siluridae generally, the small stream-dwelling species are not documented to form the same market-driven breeding programmes as the larger, food-fish Ompok and Pangasius species, and there is no record of courtship, spawning site, or fecundity for this species in the literature consulted.
Breeding
There is no record of Ompok platyrhynchus being bred in captivity, and it is not established in the aquarium trade at all — it is known only from its original type-locality collection. Among its relatives, the true glass catfishes (Kryptopterus) are essentially never bred in the home aquarium and the trade in them is entirely wild-caught; the larger river Ompok and Wallago species that are farmed for food are propagated at commercial or hormone-induced scale, not by hobbyists. Given O. platyrhynchus is smaller, rarer, and has no aquarium history at all, it is honest to say that home breeding is wholly unestablished and there is no protocol to describe.
In the aquarium
Ompok platyrhynchus is not a known aquarium fish — there is no record of it in the trade, and this account should not be read as encouragement to seek it out. It is included here for completeness as a described Bornean endemic. Its real adult size is small (under 3 in SL), so unlike many size-trap catfish it would not outgrow a modest tank, but that is moot without any husbandry data to draw on.
What can be said generally, and would apply if it were ever kept: like all Siluridae it is scaleless and therefore likely medication-sensitive, meaning copper-based treatments and many standard medications should be dosed conservatively, as with loaches, puffers, and other naked-skinned catfish. As a fast-water stream species it would be expected to need strong flow and high dissolved oxygen rather than still water. No spine hazards are documented for this species specifically, though caution moving any siluriform in a net rather than a container is good general practice for the family.
Conservation
The IUCN Red List lists Ompok platyrhynchus as Data Deficient. It is known from a single, narrow river drainage — the Temburong in Brunei Darussalam — which by itself is a restricted-range concern, but there has been no population assessment, no abundance data, and no documented threat analysis published to support a full status.
A species confined to one small stream system is inherently vulnerable to localised pressures such as land-use change, water extraction, or pollution in that drainage, even though none of these have been specifically documented as active threats here. Given the total absence of trade or husbandry pressure, any conservation concern for this species would stem entirely from habitat condition in its native Bornean stream, not from collection for the aquarium hobby.