The existence of inorganic nitrogen in the shrimp pond ecosystem will not be separated from the nitrogen cycle and microbiological processes including the activity of microbes. This study aimed to analyze the abundance and potential rate of nitrifying, denitrifying, and nitrate-ammonifying bacteria in Vanamae shrimp cultivation. Water samples were collected on a shrimp pond in Karawang, West Java. Water sampling was carried out at the age of shrimp rearing 0 days, 21 days, 65 days, and 89 days. Water sampling was conducted at four points representing an area of the pond. The bacterial abundances were analyzed using Most Probable Number (MPN) method. The potential rates of bacteria were calculated by Michaelis-Menten kinetics. The highest abundance of nitrifying bacteria was 3.690 log cells ml-1 on 65 days, denitrifying bacteria was 3.415 log cells mL-1 on 89 days, and nitrate-ammonifying bacteria was 3.079 log cells mL-1 on 65 days of shrimp cultivation. The affinity of enzymes related to ammonia oxidation from nitrifying bacteria was higher than nitrate reduction from denitrifying and nitrate-ammonifying bacteria. Generally, nitrifying bacteria were the most abundant and dominant activity over shrimp cultivation.