The project's The growth of bacteria. Rhodopseudomonas sp. In freshwater and saltwater. The objective was to study the growth of bacteria. Rhodopseudomonas sp. In freshwater and saltwater. To be used in agriculture and fisheries to benefit the most. The study and comparison of infection for 30 days by culturing. Rhodopseudomonas sp. And sampled every three days. Then, the cell dry weight compared to the growth of bacteria. Rhodopseudomonas sp. in freshwater and saltwater. This ensures that infected Rhodopseudomonas. sp., can grow in fresh water or salt water is better.