**5. Conclusions**

By analyzing the sequences of the *CO* I gene of 401 parrotfish, we found that the average intraspecific genetic distance was 0.003, and the average interspecific genetic distance was 0.159, approximately 53 times the average intraspecific genetic distance. The NJ tree shows that *C. sordidus* and *C. spilurus* of blue-headed green parrotfish gather together, and individuals of other species grouped together, with high support, and different species can be effectively distinguished. The results showed that DNA barcode technology based on the *CO* I gene could be used to identify species of *Scaridae*.

**Supplementary Materials:** The following supporting information can be downloaded at: https: //www.mdpi.com/article/10.3390/jmse10121915/s1, Table S1: Mean percent genetic distances between Scaridae species under the corrected K2P.

**Author Contributions:** Data curation, B.L. (Bo Liu).; formal analysis, N.Z.; investigation, H.G.; methodology, J.Y.; resources, Y.Y., N.Z., H.G., B.L. (Baosuo Liu) and K.Z.; validation, B.L. (Baosuo Liu); visualization, J.Y.; writing—original draft, B.L. (Bo Liu); writing—review & editing, D.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by the Financial Fund of Ministry of Agriculture and Rural affairs of China (NHYYSWZZZYKZX2020), National Marine Genetic Resource Center, and China-ASEAN Maritime Cooperation Fund.

**Institutional Review Board Statement:** All experiments in this study were approved by the Animal Care and Use Committee of South China Sea fisheries Research Institute, Chinese Academy of fishery Sciences (no. SCSFRI96-253) and performed according to the regulations and guidelines established by this committee. Written informed consent was obtained from the owners for the participation of their animals in this study.

**Informed Consent Statement:** Informed consent was obtained from all subjects involved in the study. Written informed con-sent has been obtained from the patients to publish this paper.

**Data Availability Statement:** All data generated or analyzed during this study are included in this published article.

**Acknowledgments:** This work was supported by the Financial Fund of Ministry of Agriculture and Rural affairs of China (NHYYSWZZZYKZX2020), National Marine Genetic Resource Center, and China-ASEAN Maritime Cooperation Fund.

**Conflicts of Interest:** No potential conflict of interest was reported by the authors.
