is an endemic fish in the upper Yangtze River. Due to overfishing, hydropower development and other human activities, the natural resources of have decreased during recent decades. The significance of behavioral studies for animal protection is widely accepted. The compilation and analysis of ethograms is the basis of further research on animal behavior. Due to variations in living environments, accurate ethograms of fish should be based on behaviors obtained from natural or semi-natural conditions. The present study aims to establish the behavioral ethogram of in nature. From November 2015 to March 2016, field behavioral observations of were conducted in the Guosheng River, which is located in Sichuan Province, China. A short reach of the Guosheng River, with a length of about 100 m and width of 10 to 13 m, was enclosed as the observation site. A total of 56 pairs of mature parents were released to the enclosure. The river could pass through the enclosure, but experimental fish could not escape. The behaviors of were recorded using underwater cameras and sampled by focal animal and was coded under the "posture, act, and environment" (PAE) coding system. A total of 10 postures, 22 acts, and 43 behaviors were recorded. According to biological functions, the recorded behaviors of were divided into 11 types, including ingestion and elimination, exploration, territoriality, estrus, mating, epimeletic, conflict, locomotion, aggregation, rest and sundry. The relative frequency and occurrence season of each behavior in relation to gender and juvenile were also given out. The behaviors of the juveniles were relatively simple and mainly related to ingestion, elimination, aggregation, and resting. The behaviors of matured were diversified with obvious gender differences, especially in the reproductive behaviors. During the reproductive season, female spent most of the time resting and showed few behaviors such as swimming or mating. While male showed various behaviors, especially endemic behaviors like territorial behavior, sneak mating, and epimeletic behavior. Gender differences in behaviors may reflect the reproductive strategy of , in which more energy is allocated for oocyte development in females and for behavior in males. The behavioral types of aquatic animals are significantly fewer than that of terrestrial higher animals, which may relate to the lower evolutionary level and simpler living environment of aquatic animals. The present study may enable further behavioral and protection research in , and give a reference to behavioral ethogram studies in other fish species.