Abstract
Pleistophora priacanthusis sp. nov. is described from big‐eyes, Priacanthus tayenus and P. macracanthus, from the South China Sea. The clinical signs, prevalence, intensity and site of infection of the infected fish, the general effect of the parasite on the host, seasonal distribution and sex differences are reported. The morphology of cysts, spores, sporonts and the characteristic features of the new species using the light microscope are described.