Taxonomy & naming
Microctenopoma pekkolai was described by the Swedish ichthyologist Hialmar Rendahl in 1935. The valid name, as listed in Eschmeyer's Catalog of Fishes, is Microctenopoma pekkolai (Rendahl, 1935); the parenthetical authority reflects the species' original placement in a different genus before its transfer to Microctenopoma.
Microctenopoma is a genus of small African labyrinth fishes in the family Anabantidae, closely related to the larger Ctenopoma. The genus currently comprises around fourteen recognised species, all native to sub-Saharan Africa and all sharing the air-breathing labyrinth organ characteristic of the broader order Anabantiformes. M. pekkolai is among the least-studied members of the genus, known primarily from the type locality on the White Nile in Sudan and seldom encountered in either scientific collections or the aquarium hobby.
Morphology
Microctenopoma pekkolai is the smallest species in the genus Microctenopoma, with FishBase recording a maximum total length of 1.5 in. This makes it exceptionally compact for a labyrinth fish — smaller than many of the dwarf gouramis commonly kept in aquaria. The body form is typical of the genus: moderately compressed laterally, with a rounded head, an upturned mouth suited to surface feeding and bubble-nest building, and the short, spiny-rayed dorsal fin shared with related anabantids.
Detailed morphological data for M. pekkolai are sparse in the available literature. Like other Microctenopoma, males are expected to be distinguishable from females by the fine spiny scales on the caudal peduncle region, a character that recurs across the genus, though specific colouration and meristic data for this species have not been widely published.
Habitat
The type locality for Microctenopoma pekkolai is the White Nile drainage in Sudan. This places it in the Nile system — an unusual distribution for a labyrinth fish, as the majority of Microctenopoma species are concentrated in the Congo basin and West Africa. The White Nile at its type-locality region flows through seasonally flooded savanna and wetland environments, with warm temperatures and waters that can become oxygen-depleted during the dry season or in stagnant pools.
As a labyrinth fish, M. pekkolai is physiologically equipped for precisely such conditions: the suprabranchial labyrinth organ allows direct extraction of atmospheric oxygen, enabling the fish to survive in warm, poorly oxygenated water that would exclude most other species. Habitat details beyond the type-locality record are not well documented, but the general ecology of Microctenopoma — slow-moving or standing water, marginal vegetation, and flooded areas — likely applies here as well.
Feeding
Specific dietary data for Microctenopoma pekkolai have not been reported in the accessible literature. By analogy with the genus and with small African labyrinth fishes generally, the natural diet almost certainly consists of small invertebrates — aquatic insect larvae, microcrustaceans, and similar prey taken from the water column and surface — consistent with the small gape imposed by a body length of under 1.5 in.
In an aquarium context, a species of this size would be offered appropriately scaled live and frozen foods: small Daphnia, Cyclops, baby brine shrimp, and similarly fine invertebrate prey. Data on specific captive feeding preferences are absent from the sources available.
Mating
Microctenopoma pekkolai is a bubble-nest builder. FishBase confirms bubble-nest construction for the species, placing it with the majority of Microctenopoma in which the male constructs a raft of mucus-bound bubbles at or near the water surface and uses it as a spawning platform and egg-guarding site.
As with related species, the male is expected to initiate courtship displays, drive the female toward the nest, and embrace her in the characteristic anabantid spawning wrap. Eggs are fertilised and deposited into or near the bubble mass. Detailed field or aquarium observations of courtship behaviour specific to M. pekkolai are not documented in the sources consulted.
Breeding
Breeding behaviour in Microctenopoma pekkolai follows the bubble-nesting pattern confirmed for the species: after spawning, the fertilised eggs are placed in or near the bubble nest, and the male guards the nest and tends the developing eggs until hatching. This paternal nest-guarding behaviour, in which the male actively maintains the bubble raft and retrieves fallen eggs, is shared across Microctenopoma and the broader Ctenopoma alliance.
No detailed captive breeding records for M. pekkolai are available in the literature reviewed. Given the species' very small adult size — 1.5 in total length — a breeding setup would require a small, quiet tank with surface access and cover, still or very gently filtered water, and appropriately sized live foods for the fry. The species is not known to have established itself in the ornamental hobby, so breeding accounts remain to be documented.
In the aquarium
Microctenopoma pekkolai is not currently a species of the mainstream aquarium trade, and aquarium-keeping accounts are essentially absent from the available literature. Its tiny adult size — under 1.5 in total length — would in principle make it suitable for small, quiet aquaria, but the near-complete absence of hobby records means water-chemistry requirements, temperament, and husbandry preferences beyond the genus-level baseline remain undocumented.
Based on the biology of closely related Microctenopoma species, such a setup would logically provide warm water (roughly 73–82 °F), a soft to moderate pH in the neutral range, dense surface cover to support bubble-nest construction, and very gentle filtration — conditions that also allow the fish to access atmospheric air without difficulty. Tankmates, if any, would need to be similarly diminutive and non-aggressive. Any keeper encountering this species should treat existing Microctenopoma care guides as a starting framework while recognising that species-specific data are sparse.
Conservation
Microctenopoma pekkolai is listed on the IUCN Red List as Data Deficient (DD). This assessment reflects the limited information available on the species' population size, distribution range beyond the type locality, and the nature and severity of any threats it faces. Data Deficient is not a conservation status in the same sense as Threatened categories — it indicates that assessment is not yet possible rather than that the species is secure.
The White Nile drainage of Sudan, where the species was described, has experienced significant hydrological changes, including large-scale dam construction and water abstraction, as well as habitat alteration from agriculture and human settlement. Whether M. pekkolai persists in these modified habitats, and across what portion of its potential range, is not established. The species has no established presence in the ornamental trade and thus no hobby-based monitoring or captive reserve population.