The non-native freshwater fishes of Hong Kong: diversity, distributions, and origins Author Chan, Jeffery C. F. Author Tsang, Alphonse H. F. Author Yau, Sze-man Author Hui, Tommy C. H. Author Lau, Anthony Author Tan, Heok Hui Author Low, Bi Wei Author Dudgeon, David Author Liew, Jia Huan text Raffles Bulletin of Zoology 2023 2023-02-22 71 128 168 journal article 10.26107/RBZ-2023-0012 2345-7600 7815765 82C3DAD3-0920-4430-A93D-9F887A58DC1A Oreochromis aureus (Steindachner) ( Fig. 33 [LU]) Distribution. She Shan River, Lai Chi Kok Park (GBIF. org, 2021); Tung Tsz Stream (current survey) Native range. Africa. Remarks. Not as widespread as other Oreochromis spp. , but the frequency of records has risen in recent years. It differs from the morphologically similar Oreochromis niloticus by having faint variable bars on the caudal fin as opposed to regular dark vertical bar, and pink-red margins ( Trewavas, 1983 ). Juveniles have a black spot at the rear of the dorsal fin, which is absent in Oreochromis niloticus ( Gu et al., 2016 ) . This species may also resemble Oreochromis niloticus × Oreochromis mossambicus hybrids, which can be preliminarily differentiated from them by the presence of blue spots on the dorsal and caudal fins and blue colouration of the snout in Oreochromis aureus .