Neolamprologus multifasciatus is a small cichlid breeding in empty gastropod shells that forms complex family groups with several reproductive males and females, presumably due to dispersal constraints. Nevertheless, some exchange of females between groups has been demonstrated. We investigated experimentally emigration patterns of female group members to elucidate which factors influence the decision of adult females either to stay or to emigrate into another territory. Four females resident in a large (13 shells) male territory were given the opportunity to stay there or to emigrate to another large (13 shells) or a small (four shells) male territory. In six replicates we found that (1) the most aggressive females had the largest subterritories (most shells); (2) invariably, the two females with the fewest shells emigrated; (3) both the emigrating and the staying females had more shells after emigration than before. Apparently, females explore their options in neighboring territories and decide accordingly whether to stay or emigrate.