The Malagarazi basin constitues about one third of the catchment area of Lake Tangyanika. Currently, 108 species are known form the entire Malagarazi basin, including 25 endemics. Nearly 60% of all species have confirmed from the Burundese part of the basin. This is noteworthy as the Malagarazi in Burundi covers only four percent of the total drainage area. The inventory is by no means complete and certain groups such ass the genera 'Barbus', Labo and Leabobarbu (Cypridinae), Synodontis (Mochokidae), and the haplochromine cichlids (Cichlidae), require further taxonomic attention. During the last three years, new sampling expeditions have been undertaken in the Upper Malagarazi in Burundi. Species identification was often problematic as, to date, no identification key is available for this fish fauna. Specimens belonging to at least two new 'Barbus' species, one new Labeobarbus (Cyprinidae) and one new Chiloglanis (Mochokidae), have been collected. One of the new species, 'Barbus' sp. 'devosi', belongs to the group of small African 'Barbus' with a strongly ossified and serrated last unbranched dorsal-fin ray and a blackish midlateral band. In 'B'. sp. 'devosi', this band extends from the tip of the snout to the caudal fin. Specimens of this species had been identified as 'B' eutaenia and 'B' miolepis miolepis. However, it can be clearly distinguished form both species in haveing: a higher number of ceratobranchial gill rakers on the first gill arch (6-9 vs 2-5); shorter anterior (10.6-19.1 vs. 20.0-34.7% HL for 'B' eutaenia and 20.3-36.5% HL for 'B' miolepis) and posterior (14.5-26.6 vs. 22.4-43.7% HL for 'B.' eutaenia and 26.5-45.7% HL for 'B.' miolepis) barbels; and by the absence of a sheath of enlarged, prominent, scales at the base of the dorsal fin. the high species diversity within this small portion of the Malagarazi basin in a country with increasing pressures on its natural resources underscores the importance fo the national reserve in that area, that is currently being set up