The haplochromine cichlid fish communities of the rocky habitats of Lake Malawi are
highly diverse; however, many species live side by side with apparently very similar
resource requirements. There is a longstanding debate concerning whether these species
partition their resources on a finer scale than has been previously reported or if
species that are truly ecologically indistinguishable can coexist. A field study of
food resource use was conducted to determine whether coexisting species segregate their
diet and foraging sites. Significant differences between species were found, yet
considerable inter-specific resource use overlap was commonplace. The data indicate
that these cichlid species coexist both with and without niche differentiation. We
propose that alternatives to niche differentiation should be considered to explain how
many species coexist in Lake Malawi cichlid communities.