bidens, Opsariichthys Günther [A.] 1873:249 [Annals and Magazine of Natural History (Series 4) v. 12 (no. 69) (art. 31); ref. 2004] Shanghai, China. Holotype (unique): BMNH 1873.7.30.96. •Synonym of Opsariichthys uncirostris (Temminck & Schlegel 1846) -- (Mai 1978:120 [ref. 13511], Bogutskaya 1998:79 [ref. 23589]). •Synonym of Opsariichthys uncirostris (Temminck & Schlegel 1846), but a valid subspecies -- (Yang & Hwang 1964:40 [ref. 13497], Nguyen & Nguyen 2000:12 [ref. 26614], Sado & Kimura 2002:353 [ref. 26498]). •Valid as Opsariichthys bidens Günther 1873 -- (Kuang in Kuang et al. 1986:45 [ref. 26639], Kuang in Chu & Chen 1989:31 [ref. 13584], Zheng et al. 1989:68 [ref. 21202], Ye & Song in Pan et al. 1991:75 [ref. 23876], Ding 1994:128 [ref. 21531], Zhu 1995:26 [ref. 25213], Cheng & Zhou 1997:104 [ref. 26385], Doi 1997:8 [ref. 22832], Chen & Chu in Chen et al. 1998:47 [ref. 23878], Kottelat 2001:33 [ref. 25482], Kottelat 2001:63 [ref. 25780], Tang et al. 2001:12 [ref. 25373], Wang et al. 2001:75 [ref. 26566], Bogutskaya & Naseka 2004:99 [ref. 28183], Chen et al. 2008:217 [ref. 29934], Bogutskaya et al. 2008:333 [ref. 30085], Chen et al. 2009:175 [ref. 30298], Kottelat 2013:130 [ref. 32989], Huynh & Chen 2014:142 [ref. 33158], Zhang et al. 2016:50 [ref. 34477], Wang et al. 2019:[6] [ref. 36521], Zhang et al. 2019:135 [ref. 36699], Dyldin et al. 2020:87 [ref. 37569], Fu et al. 2021:9569 [ref. 39347], Guo 2021:92 [ref. 38617], Taki et al. 2021:85 [ref. 39830], Chen et al. 2024:11 [ref. 41608], Peng et al. 2024:29 [ref. 41610]). Current status: Valid as Opsariichthys bidens Günther 1873. Xenocyprididae. Distribution: East Asia: northern and eastern-central China and eastern Russia; introduced in the upper Mekong River basin (Laos). IUCN (2022): Least Concern. Habitat: freshwater.