This paper reported the changes in the community structure of Cladocera in the shallow, hypertrophic Lake Donghu from 1980 to 1995. This lake lacking macrophytes is densely stocked with two planktivorous filter-feeding fishes. The most striking events of the cladoceran community were that the large-sized Daphnia carinata ssp. which dominated in summer before 1985 were replaced by the smaller Moina micrura afterwards, and that drastical decline in the population of another large-sized Daphnia hyalina also occurred. Meanwhile, the total cladoceran abundance also declined severely. Neither nutrient amount nor the change in phytoplakton community can be used to explain the remarkable changes in cladocerans satisfactionally. From 1980 - 1995, fish yield (more than 85% from silver and bighead carps) increased steadily (from 545 to 1056 kg/hm-2). Increased predation pressure by the planktivorous fishes is considered to be the driving force in changing the community structure of cladocerans in the 1980s.