Taxonomy & naming
Microctenopoma ocellifer was described by the American ichthyologist John Treadwell Nichols in 1928, based on material collected at Ankoro — the junction of the Lualaba and Luvua rivers in what was then the Belgian Congo and is now Katanga Province, Democratic Republic of Congo. The holotype is deposited at the American Museum of Natural History (AMNH 9253). Eschmeyer's Catalog of Fishes records the current valid name as Microctenopoma ocellifer (Nichols, 1928); the parenthetical authority indicates the species was originally placed in a different genus.
The species passed through two successive synonyms before reaching its current combination. It was first placed in Anabas as Anabas muriei ocellifer, then moved to Ctenopoma as Ctenopoma muriei ocellifer, before the genus Microctenopoma was erected to accommodate a cluster of smaller, more slender African anabantids that share a reduced ctenoid scale texture and confirmed bubble-nesting behaviour. The genus was formally characterised by Norris (1995), and M. ocellifer transferred to it at that time.
The specific epithet ocellifer is Latin, meaning "bearing an ocellus" or "eye-spotted" — a reference to the ocellated (eye-like, ringed) spot that figures in the species' markings.
Morphology
Microctenopoma ocellifer is a small, slender anabantid, with published records placing maximum total length at 2 in. The body plan is typical of the genus: moderately laterally compressed, with a pointed snout, a relatively large eye, and the slightly upturned mouth of a surface-oriented predator. The dorsal and anal fins are long-based and set far back on the body, a hallmark of the anabantid bauplan.
The common name and specific epithet both point to the diagnostic ocellated marking — a dark spot ringed by a pale or iridescent halo, positioned near the posterior soft dorsal or caudal peduncle region. Detailed colour descriptions from fresh specimens are sparse in the published literature, but patterning in live Microctenopoma typically includes scattered dark spotting or speckling on the flanks, iridescent scale highlights under raking light, and intensified coloration in displaying or guarding males. Females are generally plainer and smaller-bodied.
Habitat
The type locality of M. ocellifer is Ankoro, at the confluence of the Lualaba and Luvua rivers in Katanga Province, and FishBase records its known range as the Upemba Lake region of the upper Lualaba drainage. This is the Congo River's headwater zone — an elevated plateau system of interconnected lakes, rivers, and seasonal floodplains at the southern fringe of the Congo Basin. Lake Upemba itself lies within the Upemba National Park, one of the DRC's largest protected areas.
As a labyrinth fish and facultative air-breather, M. ocellifer can tolerate reduced dissolved-oxygen conditions that would exclude obligate gill-breathers. The species is benthopelagic in habit, occupying still or sluggish water in association with marginal vegetation, flooded root tangles, and the weedy shallows characteristic of African floodplain lakes. Specific water-chemistry measurements for its native waters are not recorded in the available literature, but the broader upper Lualaba system is a tropical freshwater environment with warm, typically soft-to-moderately-hard conditions.
Feeding
Like other small Microctenopoma, M. ocellifer is a micro-predator in the wild, targeting small invertebrates at or near the water surface and in the water column. Likely prey items include small aquatic insects and their larvae, microcrustaceans, and terrestrial invertebrates that fall onto the water surface — a feeding strategy shared by many small anabantids whose upturned mouths are adapted for surface feeding.
In captivity, small live and frozen invertebrate foods — Daphnia, Artemia nauplii, bloodworm, and glass worm — are the most appropriate diet and help maintain condition. Dry foods of an appropriate size are accepted by many individuals once acclimatised, but live and frozen items remain preferable for long-term health and breeding condition in what is a naturally predatory, insectivorous species.
Mating
Microctenopoma ocellifer is a bubble-nest builder — the defining reproductive strategy of the genus. Males construct a raft of mucus-bound air bubbles at the water surface, often beneath a floating leaf or in association with surface vegetation, and the nest anchors the clutch during incubation. Courtship involves the male displaying to the female beneath or near the completed nest, spreading his fins and presenting his flanks to exhibit his ocellated markings and any iridescent coloration at full intensity.
Male Microctenopoma are typically territorial around the nest site during the breeding period and will display aggressively toward rival males. The female, once receptive, approaches the nest and spawning occurs in the typical anabantid embrace — the male wraps around the female to release sperm at the moment eggs are shed. The fertilised eggs are buoyant and float into the bubble nest, where the male gathers any that sink.
Breeding
Following spawning, the male guards the bubble nest, repairing breaks in the bubble raft and retrieving eggs or early larvae that fall. Females should be removed after spawning to prevent harassment by the guarding male. The eggs hatch within a day or two at warm tropical temperatures, and the larvae initially hang vertically from the bubble nest as they absorb their yolk sacs.
Once the fry become free-swimming — typically within three to five days of hatching — the male's guarding role diminishes and he too can be removed to prevent predation on the fry. First foods for the free-swimming fry should be very small live foods such as infusoria or paramecia, graduating to Artemia nauplii and similarly fine foods as growth permits. The labyrinth organ does not develop immediately in fry; surface access to warm, humid air is important once it begins to form, so the tank should be kept covered.
In the aquarium
Microctenopoma ocellifer is an uncommon species in the ornamental trade and primarily of interest to specialists in African anabantoids. It is best maintained in a species aquarium or alongside other small, peaceful African fishes that will not outcompete or intimidate it. A well-planted tank with floating vegetation, subdued lighting, and minimal water movement suits its natural preference for calm, vegetated habitats; surface access must be kept clear so the fish can breathe air at the labyrinth organ.
Water should be warm — tropical temperatures in the mid-to-upper 20s Celsius are appropriate — and gentle filtration that does not create strong currents is preferred. The species' small size means that even a modestly sized aquarium of 23.5–31.5 in provides adequate space for a pair or small group. As with other Microctenopoma, males may be aggressive toward each other, particularly around a nest site; housing one male with one or more females is the most practical arrangement. Because wild-caught specimens may be sensitive to shipping stress and suboptimal water quality, acclimatisation should be gradual and water quality carefully maintained.
Conservation
Microctenopoma ocellifer is assessed as Least Concern (LC) on the IUCN Red List, evaluated in 2009. The 2009 assessment recorded no known threats to the species, and its range within the Upemba Lake region includes waters that fall within the Upemba National Park, providing a degree of habitat protection. The DRC's protected-area network in this region offers some buffer against the land-use pressures that threaten freshwater fishes elsewhere in Central Africa.
Nonetheless, the species' restricted range in the upper Lualaba system means it is not broadly distributed, and detailed population data are lacking. The DRC has experienced prolonged political instability that has complicated effective enforcement of protected-area boundaries. A formal reassessment with updated field surveys would provide a clearer picture of the species' current status; in the absence of more recent data, LC remains the recorded assessment.