Seasonal hydrological changes have a significant impact on the population dynamics of freshwater prawns of the genus Macrobrachium, which are an essential ecological and economic component of Bangladesh's inland fisheries. In three different freshwater habitats the lentic Chaira Beel floodplain, the lotic Brahmaputra River, and the vast Mithamoin Haor wetland this study assessed the seasonal fluctuations in species composition and abundance of Macrobrachium prawns. To determine the Catch Per Unit Effort (CPUE) of dominat species, monthly sampling was carried out using frame nets during a one-year cycle, divided into pre-monsoon, monsoon, and post-monsoon seasons. Results revealed clear successional patterns that were influenced by hydrological regimes. During the monsoon season, M. lamarrei remained the most productive, reaching a peak of 0.710 kg/gear/hour in September at Mithamoin Haor. The pre-monsoon phase, on the other hand, had the largest total community biomass, with M. villosimanus reached a maximum CPUE of 0.66 kg/gear/hour in Mithamoin during March and M. malcolmsoni peaking at 0.54 kg/gear/hour in the Brahmaputra River in April. During October, a specific peak of M. acanthurus (0.78 kg/gear/hour) happened in Chaira Beel, signaling the end of the monsoon. These findings indicate various Macrobrachium species occupy specific seasonal hydrological niches, with maximal biomass occurring when water quantities decline during the pre-monsoon period. These observations are crucial for establishing habitat-specific management strategies to ensure Bangladesh's prawn resource exploitation is sustainable.