Taxonomy & naming
Chiloglanis anoterus was described by the South African ichthyologist Pieter Crass in 1960. It sits in the family Mochokidae, the African squeakers and upside-down catfishes, within the genus Chiloglanis — the rock or suckermouth catlets, a large genus of small, flattened stream-dwelling catfish distributed across sub-Saharan Africa. The Catalog of Fishes treats Chiloglanis anoterus as the currently valid name; it has not undergone the kind of generic reshuffling seen elsewhere in Siluriformes.
The genus name Chiloglanis derives from the Greek cheilos (lip) and glanis (a catfish), a reference to the enlarged, sucker-like oral disc shared by the whole genus. The species epithet anoterus is Greek for "higher" or "upper", most plausibly a nod to the high-elevation escarpment streams — around 1,1312 ft (4,600 ft) — from which the type series was collected in the upper Pivaan River, part of the Pongola system in Natal, South Africa.
Morphology
Like other members of its genus, Chiloglanis anoterus has a flattened head and a ventral, sucker-like mouth disc used to grip smooth rock in fast current — a classic hillstream adaptation rather than a feeding-only structure. The body is small and slender, reaching a maximum of only about 3.5 in standard length, among the smaller members of the squeaker family.
The species is scaleless, as is typical for Mochokidae, and carries stiff, sharp dorsal and pectoral fin spines with an associated venom apparatus at their base — a defining feature of the genus and a genuine hazard when handling the fish. Sexual dimorphism is pronounced and easy to read at a glance: males have a distinctive pennant-shaped (elongated, streamer-like) caudal fin, while females have a plain forked tail.
Habitat
Chiloglanis anoterus is endemic to escarpment streams of the Pongolo and Incomati (Komati) river systems, found only in South Africa and Swaziland (Eswatini). The type locality — the upper Pivaan River, a Pongola tributary — sits at roughly 1,1312 ft elevation, and the species is characteristic of similar upland, fast-flowing reaches rather than the lowland mainstem rivers.
It lives in shallow, fast-flowing riffles over rock and gravel, gripping smooth stones with its suckermouth against the current. Recorded water conditions are warm-temperate to subtropical rather than tropical: 73–79 °F with a near-neutral pH of 6.5–7.2. This is a well-oxygenated, flowing-water specialist, not a still-water or blackwater fish, and it depends on clean, silt-free rock substrate to hold position and to graze.
Feeding
Chiloglanis anoterus is primarily an algal grazer, rasping biofilm and algae from the surface of rocks in its current-swept habitat, supplemented by bottom-feeding on small invertebrates and detritus much like other nocturnal benthic Mochokidae. Its suckermouth disc is as much a feeding tool as an anchor, letting it graze exposed rock faces that faster-moving fish cannot hold position on.
In the aquarium it has been kept on algae along with fly larvae, bloodworm and flake food. Because good rock-surface algae and biofilm are part of its natural diet, a tank with some established algal growth on hardscape benefits this species more than it would a typical predatory catfish; supplement with sinking foods offered after lights-out to match its more active grazing periods.
Mating
Specific spawning behaviour for Chiloglanis anoterus has not been documented in the sources consulted. What is well established is the dimorphism that presumably underpins courtship and mate recognition: males display an elongated, pennant-shaped caudal fin against the female's plain forked tail, a visual signal unusual among small stream catfish and one that suggests some form of visual courtship display, though the details are not recorded.
As with many small Chiloglanis species from fast, rocky streams, egg-laying is presumed to occur on or under stones in the swift current typical of its habitat, following the general pattern described for the wider genus, but this has not been confirmed for anoterus specifically. Data are sparse for this narrowly distributed species, and no aquarium spawning reports were found.
Breeding
There are no confirmed reports of Chiloglanis anoterus being bred in the home aquarium in the sources available. As a small, highly specialised riffle-dweller requiring strong, oxygen-saturated current and a specific rocky substrate, it belongs to the large group of catfish that are collected from the wild rather than captive-propagated for the trade.
Aquarists should not assume a bubble-nest, cave-spawning, or open-substrate mode for this species without evidence; none is documented here. Anyone keeping this fish long-term should treat successful home breeding as unlikely and unconfirmed, and should not disturb wild escarpment-stream populations, which are naturally limited in range, to supply the hobby.
In the aquarium
Chiloglanis anoterus stays genuinely small — to about 3.5 in — but it is a demanding specialist rather than an easy community fish. It needs strong water movement from a powerful filter, well-oxygenated water, and a substrate of sand or fine gravel with smooth rocks it can grip and graze; without current and clean rock surfaces it will not thrive. Match the water to its wild range: 73–79 °F and a near-neutral pH of 6.5–7.2, cooler and less acidic than many tropical community setups.
Two care points carry over from its family. It is a scaleless catfish, so it is more sensitive than scaled fish to copper and to many medications — dose conservatively. It also carries venom-associated dorsal and pectoral spines, a genuine jab hazard; move it in a container rather than a net. Being naturally tiny and a specialist algae/biofilm grazer, it is easily outcompeted for food in a boisterous community and is best suited to a dedicated fast-flow, rocky-stream biotope tank rather than a generic tropical setup.
Conservation
The IUCN Red List assesses Chiloglanis anoterus as Least Concern (2022). Despite facing habitat pressures typical of escarpment streams — including erosion, agricultural runoff and water abstraction — the species remains abundant within the suitable rocky, fast-flowing habitat it occupies across its range in South Africa and Swaziland.
Because it is a narrow-range endemic restricted to a specific pair of river systems and a specific stream habitat type (high-gradient escarpment riffles), its long-term status is tied closely to the health of those streams even though the current assessment is not concerning. It is not established as a captive-bred aquarium fish, so any specimens in the trade should be assumed wild-collected from a genuinely limited range.