Our S.5 Biology students went to Tai Tam Reservoir for field study on 12th April, 2024. They were told to count the species and the number of the Zooplankton and Phytoplankton, in order to know more about the ecosystem. Students not only could experience the sampling process, but also gained a deeper understanding of Zooplankton and Phytoplankton. We would like to appreciate the Sea Education Association to provide experience teachers for our students.