Taxonomy & naming
Chiloglanis modjensis was described by the Belgian-British ichthyologist George Albert Boulenger in 1904. It belongs to the family Mochokidae — the African squeakers and upside-down catfishes — and to the genus Chiloglanis, a large group of small suckermouth squeakers found across sub-Saharan Africa. The Catalog of Fishes treats Chiloglanis modjensis as a valid species.
The species epithet modjensis refers to its type locality, the Modjo River in Ethiopia, a tributary of the Awash River within the Webi Shebeli drainage. Like other members of the genus, it has at times been shuffled among older catfish groupings in historical literature, but modern taxonomy keeps it firmly in Chiloglanis. Very little has been published on this particular species since its original description, and it is one of the more obscure, poorly documented members of the genus.
Morphology
Chiloglanis modjensis reaches a maximum recorded length of only about 1.5 in standard length, making it one of the smallest catfish in this atlas and a genuinely diminutive member of the family. Like all Chiloglanis, its most distinctive feature is a modified, suckermouth-like oral disc on the underside of the head, used to cling to rock surfaces in fast-flowing water — the trait that gives the genus its common name of "suckermouth squeakers".
The skin is completely scaleless, as in other mochokids, and the fish carries the stiff, serrated, locking pectoral and dorsal spines typical of the family; these can lodge in a net and jab a careless hand, so specimens are best moved in a container rather than netted. Genus-level accounts of Chiloglanis note subtle sexual dimorphism in some species — males with elongated fins or an enlarged humeral process — but nothing specific has been documented for C. modjensis itself.
Habitat
This species is endemic to the Modjo River and, more broadly, the Webi Shebeli basin of Ethiopia, where it was collected from the type locality on the Awash River system. As a Chiloglanis it is presumed to occupy the fast-flowing, rocky and well-oxygenated stretches typical of the genus, using its sucker mouth to hold position against the current on stones and rock faces.
Detailed water-chemistry data for the Modjo River population have not been published, so specific temperature and pH figures for this species are not available from the cache used here; readers should treat any numbers as genus-typical estimates for an Ethiopian highland river rather than measured values for this species specifically.
Feeding
Chiloglanis species are nocturnal benthic omnivores, grazing biofilm, algae and small invertebrates from rock surfaces after dark, and taking detritus and small prey items along the substrate. No feeding-specific data has been published for C. modjensis, but its genus-typical ecology strongly suggests the same pattern.
In an aquarium setting a fish of this genus would be expected to take sinking pellets, algae wafers and frozen foods once acclimated, offered after lights-out so it is not out-competed by more visible tankmates — though this species is not established in the hobby and specific husbandry has not been documented.
Mating
No courtship or spawning behaviour has been documented for Chiloglanis modjensis. Data on reproduction for this species is sparse to the point of being effectively absent from the available literature.
Breeding
There is no published record of Chiloglanis modjensis being bred in captivity, and no aquarium trade exists for this species. As with most small riverine Chiloglanis, breeding biology in the wild is not well studied; rather than guess at a mode, the honest statement is that reproduction in this species is undocumented.
In the aquarium
Chiloglanis modjensis is not an aquarium species — it is not known to be collected or traded, and this account exists for reference rather than as a stocking guide. If it were ever kept, its real size (a tiny maximum of about 1.5 in) would still call for the same care baseline as its genus-mates: strong current and high oxygenation to mimic its rocky-river habitat, a scaleless/plated skin that is sensitive to copper and many medications (dose conservatively), and locking pectoral and dorsal spines that make it easier to jab a hand or snag a net than most fish its size — move it in a container rather than netting it.
Because nothing has been published on husbandry for this exact species, none of the above should be read as tested guidance — it is a genus-level baseline only.
Conservation
The IUCN Red List lists Chiloglanis modjensis as Data Deficient, reflecting the lack of recent assessment and the general scarcity of information on its population, range extent and threats. It is known only from the Modjo River and the wider Webi Shebeli/Awash basin in Ethiopia, a region under increasing pressure from water abstraction, agricultural runoff and habitat modification, but no species-specific threat data has been published to confirm how these pressures affect it.