Animal personalities are defined as consistent individual differences in behaviors across contexts and time. Recently, the ecological relevance of personalities in fish species has drawn much attention from behavioral ecologists, and scientists assumed that how fish group members adjust their personalities thus to maintain consensus direction alignment and speed synchronization during shoaling might be of utmost importance in the field of animal behavior. To investigate the effect of personality composition on the characteristics of shoaling behavior and its internal mechanism in juvenile Qingbo (Spinibarbus sinensis), we measured the personality traits (i.e. activity and sociability), the collective motion of fish shoals (six individuals each shoal and 14 shoals each treatment) with different personality composition (proactive, reactive and heterogenous personality shoals), and the individuality of motion of each group member. The main results are as follows:(1) Qingbo showed stable personality traits with relatively large inter-individual variation indicated by high intraclass correlation coefficient and large coefficient of variation. (2) The high-activity shoals presented more percent time spent moving (approximately 18%) and higher synchronization of swimming speed (approximately 3%) compared to those of low-activity shoals, whereas there was no significant difference between either homogeneous shoal and the heterogenous personality shoal. Furthermore, the synchronization of swimming speed of high-sociability shoal was significantly lower than those of low-activity (approximately 4%) and heterogenous shoals (approximately 3%), whereas there was no significant difference in the latter two treatments. (3) The activity trait was positively correlated with the motion characteristics (such as swimming speed and its synchronization) of each group member during shoaling. The sociability trait was not only correlated (negatively) with above mentioned motion characteristics, but also negatively correlated with the group cohesion. The results suggest that:(1) the personality composition has profound effect on shoaling behavior, but with distinctly different underlying mechanisms. The shoaling behavior characteristics of the group comprised members with different activity trait are mainly determined by all the members of the group, i.e. average-determined mechanism. However, the shoaling behavior characteristics is mainly determined by a few members with the lowest sociability score, i.e. minority-determined mechanism. (2) The activity trait of the experimental fish can withhold to a large extend which might be the fundament of the average-determined mechanism. However, the positive correlation between sociability trait and group cohesion might be at least one reason for the minority-determined mechanism. In all, the stable personality with larger inter-individual variation, the close relationship between personality traits and the motion characteristics, and the complicated mechanism underlying the relationship might beneficial for Qingbo to fulfill their physiological activities under a changeable environment.