RESUMEN
When presented with stimulus shoals of siblings and conspecifics in equal number, P. sarana subnasutus were able to discriminate their siblings and preferred to associate with them. Given a choice between large shoal and a small shoal consisting of siblings, the juvenile fish preferred to associate with larger stimulus group to the smaller one. However, juveniles traded off their preference for sibling shoal with large non-sibling conspecific stimulus group, regardless of the possible benefits gained from associating with sibling shoals. The results reveal the ability of fish to discriminate their siblings during their early developmental stage and the overriding influence shoal size in the context of shoaling preference in P. sarana subnasutus.