Taxonomy & naming
Cranoglanis henrici was described by the French zoologist Léon Vaillant in 1893. For much of the twentieth century its status was unsettled — cranoglanidid catfishes were at times treated as synonyms of, or confused with, other Asian catfish lineages, and only careful comparative work confirmed henrici as a valid, distinct species separate from its relative Cranoglanis bouderius. A peer-reviewed revision (published in the journal covering Indochinese ichthyology) formally reaffirmed Cranoglanis henrici (Vaillant, 1893) as a valid cranoglanidid species from Indochina, fixing the name and authority now followed by the Catalog of Fishes.
The genus Cranoglanis is the only genus in the family Cranoglanididae, a small, distinctive lineage of Asian catfishes whose closest relationships within Siluriformes have themselves been debated; some earlier classifications placed cranoglanidids near the sheatfishes (Siluridae) or bagrids before the family was recognised as its own line. The species epithet henrici honours a personal name (a Latinised patronym, in the tradition of nineteenth-century French zoological naming), a common convention of the era rather than a description of the fish itself.
Morphology
Cranoglanis henrici reaches a documented maximum of about 11.5 in standard length, a genuinely medium-to-large river catfish rather than a nano species — the size trap matters here, since a juvenile a few centimetres long will keep growing toward that mark. Like other cranoglanidids it has a naked, scaleless skin, a streamlined, cylindrical body suited to living and swimming near the bottom in flowing water, and barbels used to feel out food on the substrate.
As in most catfishes, the dorsal and pectoral fins carry stiff, serrated spines that lock erect; these can snag a soft aquarium net and jab an unwary hand, so this species is best moved in a container rather than netted. The scaleless skin that gives it its smooth, naked appearance also makes it more permeable to substances in the water — a point that carries directly into how it should be medicated (see "In the aquarium").
Habitat
This species is native to the Red River (Song Hong) drainage spanning southern China and northern Vietnam. It lives on or near the bottom in moderately to slowly running water over sandy and muddy substrates, and is reported to form loose colonies, occurring mainly in the downstream sections of its river system rather than fast headwater reaches. Cited flow requirements for its habitat run from roughly 66 ft³/s at a minimum up to an optimal figure near 295 ft³/s, underlining that this is a fish of substantial lowland river channels, not small streams.
Spawning in the wild is seasonal, reported for the period from May to July, coinciding with the warmer, wetter part of the year in this part of Indochina. Detailed water-chemistry data (pH, hardness) for the species has not been captured in the sources reviewed here; what is documented is the physical habitat — soft sand/mud bottoms in flowing, warm-region rivers of southern China and northern Vietnam.
Feeding
Cranoglanis henrici fits the general pattern for its family and for river catfishes generally: a nocturnal, bottom-foraging omnivore that works sandy and muddy substrates for invertebrates, detritus and other small food items, most actively after dark. Specific dietary study of this species has not turned up in the available sources, but its habitat — soft-bottomed, flowing water it shares with typical benthic invertebrate communities — points to opportunistic bottom feeding rather than a specialised diet.
In captivity, a fish with this build and lifestyle would be expected to take sinking pellets, frozen foods and other prepared foods offered at the substrate, ideally after lights-out so it is not out-competed by more visible, daytime tankmates. No aquarium feeding records for this species were found in the cache, so this should be read as an inference from its family and habitat rather than a documented account.
Mating
No documented account of courtship or spawning behaviour for Cranoglanis henrici was found in the sources reviewed. What is known is limited to a wild spawning season of May to July, inferred from population and life-history data rather than direct behavioural observation. Data on this stage of the species' life history is sparse, and nothing should be inferred beyond the recorded season.
Breeding
Breeding of Cranoglanis henrici has not been documented in captivity in the sources reviewed here, and no parental-care or nest-building behaviour has been recorded for the species. Its river-colony lifestyle and moderate-to-large adult size put it in the same broad category as many mid-sized Asian river catfishes that are simply not bred in home aquaria; where such species are propagated at all it is typically wild-collected broodstock or, for commercially important relatives, hormone-induced spawning at a farm scale, not a hobbyist tank event. In the absence of any specific record for this species, the honest statement is that its breeding biology in the aquarium is unknown and it should not be assumed to be a home-breedable fish.
In the aquarium
Cranoglanis henrici is essentially unknown in the aquarium trade and has no established aquarium-care track record in the sources reviewed, so anyone encountering it should treat it with the same caution given to any little-known river catfish. It is not a small fish — a documented 11.5 in standard length means it will eventually need a large tank footprint sized for an adult river catfish, not the small growing-out tank it might start in; do not assume it will stay pot-sized.
Because it is scaleless like other cranoglanidids, it should be treated as medication-sensitive: dose copper-based treatments and other medications conservatively, as is standard practice for naked-skinned catfishes, loaches, puffers and eels. It also carries the locking, serrated dorsal and pectoral spines typical of catfishes, which tangle in nets and can jab the handler, so it is best moved in a container rather than netted. As a species reported to favour flowing water over sand and mud with a colony structure, a large, well-filtered, current-carrying setup with a soft substrate and other individuals would be the closest approximation of its wild habitat, though this is inference rather than a tested aquarium regimen. Given how little is documented about it in captivity, it is best regarded as a fish for the experienced keeper willing to work from first principles rather than an established care sheet.
Conservation
The IUCN Red List assesses Cranoglanis henrici as Least Concern, an assessment dated August 12, 2010. This reflects a species with a defined but not currently threatened range across the Red River drainage of southern China and northern Vietnam, without documentation of severe population decline in the sources reviewed.
As with many river fishes of this region, the species' long-term outlook is tied to the health of its specific river system — flow regulation, damming, sedimentation and pollution pressures on the Red River drainage are the kind of generic threats relevant to a lowland, flow-dependent species like this one, even though no species-specific threat assessment beyond the LC listing was found here.