This study provides the first comprehensive information on the parasite fauna of the white-streaked grouper Epinephelus ongus. A total of 35 specimens from the archipelago Karimunjawa, Java Sea, Indonesia were studied for metazoan parasites. For comparison, the documented parasite community of 521 E. areolatus, E. coioides and E. fuscoguttatus from previous studies were analysed. A total of 17 different parasite taxa were recognized for E. ongus, including 14 new host and four new locality records. This increases the known parasite taxa of E. ongus by more than 80%. The ectoparasite fauna was predominated by the monogenean Pseudorhabdosynochus quadratus resulting in a low Shannon index of species diversity of the entire parasite community (0.17). By contrast, the species diversity excluding the ectoparasites reached the highest value recorded for Indonesian epinephelids (1.93). The endoparasite fauna was predominated by generalists, which are already known from Indonesia. This demonstrates the potential risk of parasite transmission through E. ongus into mariculture and vice versa. One-way analyses of similarity revealed a significantly different parasite community pattern of E. ongus compared with E. areolatus and E. fuscoguttatus as well as minor differences with E. coioides. This finding refers to different habitat preferences of these epinephelids within the analysed size range.