This study aims to measure the impact of human activities on the biodiversity of fish in three sampled areas of the An Giang province of Southern Vietnam. The fish samples were gathered between August 2018 and July 2019 by collecting fish at 6 sampling sites of the regions. Using various trapping mechanisms, the V-shaped net, plastic and bamboo fish traps was applied during rice collection periods. The result found that the biodiversity indexes of the regions were 1.321, 0.078, and 7.579 for Shannon-Weaver's diversity, Simpson's dominance, and Margalef's abundance respectively. These biodiversity indexes suggested the fish assemblage inside the dike both islets and riverine regions to be lower than that of the outside sampled areas due to both the natural factors (tides and precipitation) and artificial factors (intensive farming, demand of crops, uses of agricultural chemicals and flood prevention dike system). It transforms the different dominant fish species where the new species of ichthyofauna in An Giang, Vietnam can be the potential for rice-fish farming in the near future.