Taxonomy & naming
Lophiosilurus nigricauda was described by G. F. Mees in 1974 as Pseudopimelodus nigricauda, based on material from the Sipaliwini River in Suriname. It was subsequently moved into Cephalosilurus, the genus used on this page, within the family Pseudopimelodidae (subfamily Batrochoglaninae) — the bumblebee and dwarf pimelodid-relatives of South America. Eschmeyer's Catalog of Fishes, the standing authority on valid names, currently lists this species under yet another combination, Lophiosilurus nigricauda, reflecting how unsettled the genus-level taxonomy of this small group of broad-headed pseudopimelodids has been; this profile follows the widely used combination Lophiosilurus nigricauda.
The species epithet nigricauda is Latin for "black tail", from niger (black) and cauda (tail), describing the dark tail marking used to distinguish it from its congeners. Cephalosilurus itself combines Greek kephale (head) with Silurus, the old Eurasian catfish genus name, a nod to the broad, heavy head shared by the genus's few species.
This fish was long listed as Cephalosilurus nigricaudus; Eschmeyer's Catalog of Fishes places the species in Lophiosilurus, and the current combination Lophiosilurus nigricauda is followed here.
Morphology
Lophiosilurus nigricauda has the broad, flattened head and heavy-bodied build typical of Pseudopimelodidae, tapering to a stout tail marked with the dark blotch that gives the species its name. Like virtually all catfishes it is scaleless, with naked skin rather than bony plates — a detail that matters directly for medicating it (see "In the aquarium"). It carries stiff, serrated pectoral and dorsal spines that can lock erect; these snag readily in a net and can jab an unwary hand.
FishBase gives a maximum length of 13.8 in TL, but field observations reported by hobbyist sources suggest wild individuals can reach 19.7 in — a substantial predatory catfish by any standard. Growth is reportedly fast early on, with specimens reaching around 15.7 in within about 18 months before growth slows. Keepers should plan around the larger figure rather than assume the fish will stay small; the size trap is the single most common way this species outgrows its keeper's expectations.
Habitat
The species is native to Suriname, with its type locality on the Sipaliwini River and confirmed records from several other river systems in the same drainage network, including the Tapanahony River, Gran Mau, Suriname River, Maka Creek and the Corantijn River. These are fast-flowing tropical rivers and rapids rather than still blackwater swamps.
Within these rivers Lophiosilurus nigricauda is found in pools and backwaters associated with rapids and fast-flowing stretches, over substrates of sand, rock and decaying wood — cover that suits an ambush predator waiting out the day before hunting after dark. Reported water conditions are tropical but only moderately soft: temperature around 68–77 °F, pH 6.0–7.5, with moderate hardness (around 20 dH). This is not an extreme soft, acidic blackwater fish; it sits in a fairly ordinary tropical river range.
Feeding
This is a nocturnal, benthic predator. In the wild it takes live prey, including small fish, hunting mostly after dark from cover near rocks and wood. Its large stomach lets it take a substantial meal and digest it over several days rather than feeding little and often.
In the aquarium it can be conditioned off live food onto dead or prepared substitutes — strips of fish or shrimp, and other meaty foods offered after lights-out — though some individuals may need patience to switch. Because it naturally forages at night, feeding is best timed for after the lights go off so the fish is not competing with diurnal tankmates it may in any case try to eat.
Mating
No courtship or spawning behaviour has been documented for Lophiosilurus nigricauda in the available literature. Hobbyist and reference sources describe breeding information for the species as scarce to essentially absent, and it is not reported to have been bred in home aquaria.
Breeding
Lophiosilurus nigricauda is not known to have been bred in captivity. This is consistent with the wider pattern among South American pseudopimelodids and pimelodid relatives, where large predatory species are rarely if ever spawned by hobbyists; where breeding does occur commercially in related large catfishes it typically relies on hormone induction rather than natural aquarium conditions. Absent documented spawning accounts, this profile makes no claim about the species' natural breeding mode, parental care or fecundity — those simply are not recorded.
In the aquarium
This is a large, aggressive, specialist predator, not a community catfish, and its real adult size — up to 19.7 in by field reports, well above the 13.8 in FishBase figure — needs a very large, long tank with a secure, tight-fitting lid to match. Reports describe it as notably more aggressive than its Cephalosilurus relatives, with a documented habit of attacking unprotected heaters and pump intakes, so equipment should be guarded or heavy-duty, and tankmates need to be too large to be eaten and robust enough to tolerate a boisterous neighbour.
Because it is scaleless, it is more sensitive than scaled fish to copper-based medications and many general treatments — dose conservatively, generally at half the labelled rate, and monitor closely. It also carries locking, serrated pectoral and dorsal spines that catch in aquarium nets and can jab the keeper, so it is best moved in a container rather than netted. Provide rockwork, wood and cover for daytime retreat, feed after dark, and expect a genuinely nocturnal fish that is rarely seen foraging by day.
Conservation
Lophiosilurus nigricauda has not been evaluated by the IUCN Red List, so its conservation status is formally Not Evaluated. It is known from a handful of river systems within Suriname's interior, all part of the same broader drainage network, and there is no published population trend or threat assessment to draw on.
As with many range-restricted South American catfishes described from a single country's rivers, the lack of assessment reflects limited research attention rather than any known security. Any aquarium supply is presumed to be wild-collected given the absence of documented captive breeding.