Recent research has distinguished between the components of competency and affect in students' academic self-concept. The competency component operates on the basis of a comparison with peers. This comparison may lead to a big-fish-little-pond (BFLP) effect. To investigate the sustainability of the BFLP effect, a sample of 7th graders from 6 classes in a high school in China was surveyed on both the competency and affect components of school self-concept (N = 295) at the beginning, in the middle and by the end of grade 7 and compared across 4 groups categorised according to their high school entrance exam scores. Analysis of variance results showed that the highest scoring students had the highest self-concept of competency and the scores remained high throughout the year of 7th grade. In essence, the "big fish" remained big and the "small fish" remained small, and the pattern was consistent over time. The scores for the component of affect did not differ across groups, became slightly higher in mid-year, and remained high throughout the year. Instead of attempting to promote a positive affect in schooling, there seems to be a stronger need for enhancing a sense of competency in the "smaller fish".