Taxonomy & naming
Pangasius delicatissimus was described by the Dutch ichthyologist Pieter Bleeker in 1863, the same year and author that produced several other Pangasius species from the region, including P. nasutus. It belongs to the family Pangasiidae, the shark catfishes, within the genus Pangasius, a group of medium-large to very large river catfishes native to fresh water in South and Southeast Asia. The Catalog of Fishes (Eschmeyer, California Academy of Sciences) is the authority for the currently valid combination.
Pangasiid taxonomy has been repeatedly revised, and species-level records for P. delicatissimus are sparse in the modern literature; some sources treat it as a poorly known or infrequently recorded taxon within the genus rather than a well-studied species, and it is not the well-known food or aquarium fish that P. bocourti or P. hypophthalmus are. The genus itself sits in Pangasiidae, distinguished from Siluridae and other Asian catfish families by its shark-like forked tail and streamlined, laterally compressed body.
Morphology
As in other Pangasius, the body is elongate, laterally compressed and streamlined, with a forked, shark-like tail that gives the group its common name of "shark catfish." The head is relatively small for the body, the mouth bears short barbels, and the dorsal fin is tall with a stiff leading spine. The skin is scaleless (naked), a trait shared across Pangasiidae and relevant to medication dosing (see "In the aquarium").
Members of the genus Pangasius, including this species, are reported to reach roughly 35.5–51 in in length as adults — a substantial, pond- or public-aquarium-scale fish rather than anything suited to a typical home tank. Juveniles sold in the trade are small, silvery and unremarkable-looking, which is part of why the eventual adult size so often surprises keepers.
Habitat
Pangasius delicatissimus is native to fresh water in South and Southeast Asia, in the river systems occupied by the wider Pangasius radiation — large, turbid, warm lowland rivers and their floodplains. Like other pangasiids it is a mid-water to bottom-dwelling river fish rather than a still-water or lake species.
Detailed locality and water-chemistry data specific to this species are sparse in the available literature; broadly, Pangasius species inhabit warm, well-oxygenated, often turbid tropical river water rather than soft, acidic blackwater. Data on this species' precise native range and preferred water parameters is limited — treat general Pangasius river conditions (warm, moving, moderately hard) as a guide rather than a species-specific measurement.
Feeding
Pangasius delicatissimus is a large-bodied predator and omnivore-to-piscivore in the pattern typical of its genus: a nocturnal hunter that takes fish, aquatic invertebrates and other food items it can overpower and swallow. As with all large Pangasius, any tankmate small enough to fit in its mouth should be regarded as potential food rather than a companion.
In captivity, Pangasius species accept large meaty foods — whole or chopped fish, prawn and other seafood, and large sinking pellets — readily once established. Because of its eventual size, feeding this species means committing to a correspondingly large volume of food and waste output, which is one more reason it belongs in a pond, public aquarium or large aquaculture system rather than a home tank.
Mating
Wild reproductive behaviour for Pangasius delicatissimus specifically is not well documented in the available sources. Large Pangasiidae generally undertake river migrations tied to seasonal flooding to reach spawning grounds, a pattern well studied in the commercially important P. bocourti and P. hypophthalmus and presumed broadly similar across the genus, though data sparse for this particular species.
In captivity — home aquaria in particular — Pangasius essentially do not spawn: the fish never reaches sexual maturity or the space needed to express natural courtship and spawning behaviour in a tank. Any reproduction of aquarium-relevant Pangasius species happens at commercial aquaculture facilities under controlled, hormone-induced conditions, not through natural pairing in a home setup.
Breeding
Pangasius delicatissimus is, in practice, not bred in the home aquarium. Large commercial Pangasiidae are propagated at aquaculture scale using hormone-induced spawning (commonly with pituitary extract or synthetic hormone injections) followed by stripping and artificial fertilisation — a technique developed for food-fish species in the genus and standard across pangasiid culture. There is no record of this species being spawned by hobbyists, and its adult size alone makes home breeding essentially impossible.
Parental care in Pangasius is minimal to absent once eggs are released; commercial hatcheries manage incubation and fry-rearing artificially rather than relying on any brooding behaviour from the adults. Anyone encountering this species in the trade should assume every specimen originated from a hatchery or wild collection, not a home breeding project.
In the aquarium
This is a size-trap species and that has to be stated plainly: Pangasius delicatissimus, like its genus-mates, grows to roughly 35.5–51 in as an adult, and the small, cheap juvenile sometimes sold under a Pangasius or "shark catfish" label will outgrow essentially every home aquarium within a year or two. Prospective keepers should not buy one without a firm plan for a pond, a public-aquarium-scale system, or rehoming — this is not a fish for a standard tank, however large it may seem at purchase.
Because the skin is scaleless, Pangasius are more sensitive to copper-based medications and many standard treatments than scaled fish; conservative, often half-strength dosing is advised, as with loaches, puffers and other naked-skinned catfish. The fish also carries a stiff, potentially locking spine at the leading edge of the dorsal fin typical of catfish, which can tangle in a net — move a Pangasius in a submerged container rather than netting it. It is a nocturnal predator, so any large enclosure should include open swimming space, subdued lighting, and only tankmates too large to be swallowed.
Conservation
The IUCN Red List has not published a species-specific assessment for Pangasius delicatissimus that could be located in current sources, so its status here is recorded as Not Evaluated. This reflects a genuine data gap rather than a finding of low risk — many regional Pangasiidae outside the handful of heavily studied food-fish species remain formally unassessed.
As a river fish of South and Southeast Asian lowland systems, this species would be expected to face the pressures common across the genus and region: damming and altered river hydrology, overfishing, habitat degradation and water pollution. Without a dedicated assessment or population study, its conservation status and the scale of any of these pressures on P. delicatissimus specifically cannot be stated with confidence from available sources.