AHL (1924a: 54-55) described Panchax Bualanus (=BUA) based on a single specimen from "O-Sanga Uham, 1200 m, Buala, Grassland, Cameroon." This holotype, still housed in the fish collection of the ZMB (ZMB 21947), is in poor condition today, with most fin rays broken off and the "large number of narrow light crossbands over the body" noted by AHL no longer discernible due to alcohol bleaching, leaving only small white spots.

AHL’s description of BUA is notably inadequate. HOLLY (1930: 214) refined some of AHL’s data, but these improvements still fail to align BUA definitively with any known Aphyosemion species. AHL placed BUA in the kinship of Aphyosemion Lujae (BOULENGER, 1911) and Aphyosemion Cameronense (BOULENGER, 1903). HOLLY, however, considered it a synonym of Aphyosemion Cameronense, though he lumped various distinct forms under that name, including some synonymous with Aphyosemion Exiguum.

SCHEEL (1968: 133-139) identified the type locality of BUA, Buala, near the watershed between the upper Sangha and Uham rivers, marking the boundary between the Congo and Chad basins in what is now the Central African Republic. In 1966, 100 km west of this site, SCHEEL collected an Aphyosemion species he identified as BUA. Since then, BUA has been understood as a species of the Cameroonian highlands, spanning from eastern Nigeria to western Central African Republic.

In my view, the holotype of BUA does not belong to the subgenus Kathetys (HUBER, 1977) and differs from the species SCHEEL identified as BUA since 1966. Instead, it aligns with the subgenus Mesoaphyosemion (RADDA, 1977). Previously, BUA sensu SCHEEL was considered the northeasternmost Aphyosemion species, but BLACHE (1964: 222, 223) reported another from the Chad basin, identified as Aphyosemion Cameronense. His illustration (p. 467, fig. 125), though not detailed, suggests a Mesoaphyosemion species—lacking the pointed dorsal and anal fins typical of Kathetys. True Aphyosemion Cameronense, however, inhabits rainforests of southern Cameroon and northern Gabon, raising doubts about BLACHE’s identification.

Whether BLACHE’s specimens match the BUA holotype remains uncertain; their descriptions and patterns show similarities but also differences. Regardless, I find no agreement between AHL’s holotype and SCHEEL’s BUA. Key differences include: the head and snout of BUA’s holotype are longer, with a less wedge-shaped, more cylindrical forebody; its caudal peduncle is shorter and taller; the caudal fin base is narrower (though the fin itself is nearly destroyed); and the gill cover’s rear edge is less steep than in SCHEEL’s fish. Overall, SCHEEL’s BUA has a more parallel dorsal-ventral profile, while the holotype’s is more arched.

Given these discrepancies, SCHEEL’s identification of his fish as BUA—based solely on proximity (100 km) to the type locality and AHL’s vague description—was premature. While some uncertainty persists due to the holotype’s condition, I propose that an undescribed Aphyosemion species, possibly unique to the western Central African Republic highlands and matching BUA’s holotype, exists but remains uncollected alive. Conversely, SCHEEL’s fish aligns unmistakably with Panchax Elberti (=ELB) AHL, 1924. SCHEEL treated ELB as a synonym of BUA, but their type localities are close, and only new collections at Buala could confirm BUA’s identity. I contend that what has been called BUA is, in fact, ELB.

AHL described BUA with "a large number of narrow light crossbands," while SCHEEL’s fish show red vertical stripes that likely fade to light streaks in alcohol. This discrepancy might suggest the current holotype isn’t AHL’s original specimen, though an exchange seems unlikely. Only fresh collections at the type locality can resolve this ambiguity.