AbstractChenderoh Reservoir on the Perak River, Malaysia, is a small tropical reservoir. Being a flow‐through reservoir, the water‐level management and retention time of the reservoir are dependent on the water management schemes of the three upper reservoirs. The fish biodiversity in the reservoir is relatively higher than that shown by areas downstream of the reservoir. Most species found in the downstream area are‘r’strategists in contrast to those in the reservoir where‘K’strategist species are more abundant. Biodiversity is higher in the reservoir possibly due to the higher number of niches available through the inundation of the shoreline and the creation of various coves and bays. There is, however, a reduction in biodiversity in the reservoir over time. This reduction could be due to environmental perturbation caused by land‐use activities along the shoreline of the reservoir. Although the fish standing stock is relatively low, small artisanal fisheries exist in the reservoir supporting the local communities. In order to maintain sustainability of the fisheries, the local fishers have been practising community‐based management since the early 1980s and prior to the official enactment of the Perak State Fisheries Riverine Rules. In general, because of the sensitivity of tropical reservoirs to environmental perturbation as well as limited living space created by the existence of a permanent thermocline, tropical reservoirs should be properly managed so as to protect and maintain their biodiversity and sustainability through wise use of the aq