Shoal choice studies have revealed that fish have cognitive abilities to discriminate between groups of different composition. In this work, the role of social status (based on aggressive acts) of both the test fish and the fish in the stimulus shoals was examined because of the fitness-related consequences that group association may have for the test individual. Single angelfish of high and low social status (dominant and subordinate) were presented with a choice between two stimulus shoals composed of three conspecifics of equal size and familiarity but of social status equal to, and different from that of the test fish in the same dominance hierarchy. Test fish, irrespective of the social status, spent significantly more time shoaling with subordinates that with dominants. They also initiated shoaling behaviour with subordinates more readily and the number of visits to the preference zone close to the subordinates was greater than that to dominants. The tendency was greater in subordinate fish, which showed longer latency in approaching the shoals of dominants, and spent more time in proximity to the subordinates per visit than did dominant fish. A replicate preference test indicated that this general pattern was relatively stable for at least 2 1/2 hr. A possible factor mediating this association preference, that of familiarity, was then tested. The same protocol as before was used but unfamiliar conspecific dominants and subordinates served as stimulus shoals. In this second experiment, generally test fish did not show any significant shoaling preference. The results indicate that angelfish are capable of distinguishing the social status of conspecifics and can discriminate between shoals composed of dominants and subordinates on the basis of previous interactions. It is suggested that the tendency to avoid shoals of dominant companions may be due to the disadvantage of enhanced competition, subordinates being more affected.