Developmental stages of a haemogregarine were found within polychromatocytes and erythrocytes in Giemsa-stained blood smears from six evileye pufferfish (Amblyrhynchotes honckenii) caught at Koppie Alleen in the De Hoop Nature Reserve, South Africa. This unusual haemogregarine, Haemogregarina (sensu lato) koppiensis sp. nov., was characterized by encapsulated gamonts with recurved tails, features more common in haemogregarines infecting amphibian and reptilian erythrocytes than in those from fish. Haemogregarina koppiensis is only the third species of fish haemogregarine to have been described from South Africa.