Taxonomy & naming
Ompok pabo was described by the Scottish physician and naturalist Francis Hamilton in 1822, based on fish collected in the Ganges basin. It has carried several names over the past two centuries — Silurus pabo and Callichrous pabo among the historical synonyms — reflecting the repeated reshuffling of Old World catfish genera. The Catalog of Fishes treats Ompok pabo as the currently valid combination, and it remains in that name here.
The species sits in the family Siluridae, the sheatfishes and glass catfishes of Europe, Africa and Asia, and in the genus Ompok, a group of small to medium South and Southeast Asian river sheatfishes that includes several other food and aquarium species. The genus name derives from a local Bengali name for these fish; the species epithet pabo likewise echoes the vernacular name "pabda" still used for it across parts of its range today.
Morphology
Like other Siluridae, Ompok pabo has an elongated, laterally compressed body, a flattened head, small eyes and a wide mouth armed with bands of fine teeth. The skin is entirely scaleless — smooth and naked, as in all sheatfishes — which is an important care consideration (see "In the aquarium"). The dorsal fin is reduced to a small remnant, the anal fin is long and low, running much of the length of the body, and the caudal fin is deeply forked, giving the fish a fast, eel-like silhouette in the water.
FishBase records a maximum length of around 10 in total length, and other accounts place typical adult size in the low-to-mid 20s of centimetres — modest for a sheatfish, but still a fish that needs real swimming room and cannot be judged by the 2.5–3 in size it is often sold at as a juvenile. Colouration is a plain silvery-grey to olive above, paling to silver on the flanks and belly, with no strong pattern.
Habitat
Ompok pabo is native to the Ganges–Brahmaputra drainage and adjacent systems of South Asia, with records from Pakistan, north-eastern India, Bangladesh and Myanmar. It occupies rivers, floodplain ponds and lakes across this range, favouring slow-to-moderate current over sand, mud or vegetated bottoms rather than fast, rocky water.
Water across this range is warm, tropical-subtropical freshwater rather than the soft blackwater sometimes assumed of South Asian catfishes; PlanetCatfish care notes give a working range of about 70–81 °F with pH around neutral to slightly acidic. As a floodplain species it likely experiences some seasonal variation in water level and clarity, moving between river channels and adjacent wetlands with the monsoon.
Feeding
Ompok pabo is a piscivore — a nocturnal predator that takes small fish and aquatic invertebrates it can swallow whole, using its wide gape and fine dentition to grip rather than chew prey. In the wild it likely forages after dark over soft-bottomed river and floodplain habitat, ambushing smaller fish and invertebrates rather than actively chasing them across open water.
In the aquarium it takes meaty foods readily — whole fish, prawn and other seafood, and large sinking pellets — but should not be trusted with any tankmate small enough to fit in its mouth. Any companion fish must be chosen for size, not temperament, since a hungry Ompok pabo will treat a suitably small tankmate as food rather than a neighbour.
Mating
Little is documented about courtship or pairing behaviour in Ompok pabo specifically, and no reliable account of natural pair formation in the aquarium exists. What is known comes mostly from aquaculture and fishery biology studies conducted on wild-caught broodstock in its native Ganges–Brahmaputra range, rather than from observation of voluntary spawning in captivity.
Field and hatchery studies describe Ompok pabo as a monsoon-season breeder, spawning from June to August with a peak around July, coinciding with rising floodwaters and the seasonal flush of the river system. Females reach sexual maturity by the end of their first year, at roughly 30–40 g body weight (about 5–8 in total length), after which they are capable of contributing to that seasonal spawn.
Breeding
Ompok pabo is not an aquarium-bred fish, and keepers should not expect to reproduce it in a home tank. What breeding does occur is external fertilisation over aquatic vegetation, with small, adhesive eggs around 0.5 in — the fish scatters and abandons its spawn rather than guarding it, and there is no parental care once eggs are laid.
Commercial production, where it exists, relies on hormonally induced spawning of wild-caught broodstock using synthetic inducers such as Ovatide or Ovaprim, with ovulation following roughly 8–12 hours after injection — standard hatchery technique for a fishery species, not a home-aquarium method. No reliable home-tank breeding protocol has been established, and the trade in this species, where it appears at all, is effectively supported by wild collection or hatchery production rather than hobbyist propagation.
In the aquarium
Ompok pabo is rarely seen in the hobby and is not a beginner fish. Adults reach roughly 9–10 in, and PlanetCatfish notes that even a 45-gallon (roughly 170-litre) tank looks "very full with just three fishes" at that size — a blunt reminder that this is not a fish for a standard community aquarium, and prospective keepers should plan tank size around its real adult length, not the small size it is sold at. A single specimen or a same-species group in a large, long tank with soft or sandy substrate and subdued lighting suits it better than a mixed setup, since it is a piscivore that will eat any tankmate small enough to swallow.
Because it is entirely scaleless, Ompok pabo is more sensitive than scaled fish to copper-based medications and many standard treatments; a conservative, often half-strength dose is generally advised, as with other naked-skinned catfishes such as loaches and true eels. It is a nocturnal fish that appreciates cover — driftwood, overhangs or dense planting at the tank margins — to retreat into by day, becoming more active as the lights dim. Water in the low-to-mid 20s °C with a neutral-to-slightly-acidic pH, as noted above, suits it well.
Conservation
The IUCN Red List assesses Ompok pabo as Near Threatened, based on a 2009 assessment. It is a food fish across much of the Ganges–Brahmaputra basin, and populations face the pressures common to South Asian floodplain rivers: habitat degradation, altered flow regimes from damming and irrigation, pollution, and fishing pressure on a species that is also targeted for aquaculture and local consumption.
Because it depends on floodplain and river habitat connectivity to complete its monsoon-triggered spawning migration and reproduction, changes to seasonal flooding patterns are a particular long-term concern. Any aquarium supply of this species should be assumed to draw on wild-collected or fishery-adjacent stock rather than dedicated ornamental breeding, given the absence of an established hobbyist breeding method.