A typical shell-nest constructed by large Lamprologus callipterus males. These aggregations attract different species of obligatory and facultative gastropod-shell-breeders, which consequently live and breed in closest vicinity. The photograph shows individuals of L. callipterus, N. calliurus, N. fasciatus and two facultative "non-ossified group" shell-dwellers – Telmatochromis temporalis and T. vittatus.
Koblmüller et al. BMC Evolutionary Biology 2007 7:7 doi:10.1186/1471-2148-7-7