Five new rheophilic haplochromine cichlid species are described from the Upper Congo drainage of Zambia and the Democratic Republic of the Congo: Orthochromis mporokoso sp. nov. and O. katumbii sp. nov. from the Bangwelu-Mweru ecoregion, O. kimpala sp. nov. and O. gecki sp. nov. from the Upper Lualaba ecoregion, and O. indermauri sp. nov. from the Lufubu River of the Lake Tanganyika ecoregion. Orthochromis kimpala sp. nov, O. gecki sp. nov., and O. indermauri sp. nov. are distinguished from all currently valid species of the genus Orthochromis Greenwood 1954, except for O. torrenticola (Thys van den Audenaerde 1963), by the presence of eggspots or eggspot-like maculae on the anal fin (vs. no eggspots). The three species can be easily distinguished from O. torrenticola by having three anal spines (vs. four anal spines). Moreover, all five new species can be individually distinguished from all currently known rheophilic taxa placed in the genera Orthochromis, Schwetzochromis Poll 1948 and the rheophilic species of the genus Haplochromis Hilgendorf 1888 (e.g. H. bakongo Thys van den Audenaerde 1964, H. snoeksi Wamuini Lunkayilako & Vreven 2010, H. vanheusdeni Schedel et al. 2014) either based on meristic values, morphometric distances and colouration patterns, or on a combination of them.

A new minnow species, Enteromius thespesios, is described from the south-eastern part of the upper Congo River; that is, the Kalule Nord, the Luvilombo and the Chambeshi Rivers. Enteromius thespesios belongs to the group of the soft-rayed species of Enteromius from the Congo Basin; that is, those with a weakly ossified, flexible last unbranched dorsal-fin ray that lacks serrations along its posterior edge. Within this group, E. thespesios is most similar to E. humeralis, from which it is distinguished by a higher number of circumpeduncular scales and shorter anterior and posterior barbels.Enteromius thespesios is a rheophilic and territorial species. It exhibits a marked sexual dimorphism, with males having: a red band towards the distal edge of dorsal, caudal and, to a lesser degree, anal fin; nuptial tubercles; a longer snout; longer pectoral fins; a shorter anal fin. This study gives extensive consideration to sexual shape differences for a species of Enteromius and also briefly reviews the current knowledge of sexual dimorphism in the species of Enteromius from the Congo Basin. Some conservation issues related to the new species are also highlighted.

Within a comparative morphological framework, Hippopotamyrus aelsbroecki, only known from the holotype originating from Lubumbashi, most probably the Lubumbashi River, a left bank subaffluent of the Luapula River, is reallocated to the genus Cyphomyrus. This transfer is motivated by the fact that H. aelsbroecki possesses a rounded or vaulted predorsal profile, an insertion of the dorsal fin far anterior to the level of the insertion of the anal fin, and a compact, laterally compressed and deep body. In addition, a new species of Cyphomyrus is described from the Lufira basin, Cyphomyrus lufirae. Cyphomyrus lufirae was collected in large parts of the Middle Lufira, upstream of the Kyubo Falls and just downstream of these falls in the lower Lufira and its nearby left bank affluent, the Luvilombo River. The new species is distinguished from all its congeners, that is, firstly, from C. macrops, C. psittacus and C. wilverthi, by a low number of dorsal fin rays, 27-32 (vs. higher, 36 (37), 34 (33-41) an 38 (38-40), respectively) and, secondly, from C. aelsbroecki, C. cubangoensis, and C. discorhynchus by a large prepelvic distance, 41.0-43.8% L S (vs. shorter, 39.7%, 38.9-39.1% and 37.0-41.0% L S , respectively). The description of yet another new species for the Upemba National Park and the Kundelungu National Park further highlights their importance for fish protection and conservation in the area. Hence, there is an urgent need for the full integration of fish into the management plans of these parks.