Cichlid fishes that seem specialized phenotypically to exploit certain resources often act as
generalists in the field. It is attempted to resolve this paradox by measuring feeding
performance. There are two ways of feeding, namely suction feeding and biting, that set
conflicitng demands on the anatomy. Rock-dwelling cichlids of the genus Neochromis are
specialized biters, feeding largely on filamentous algae and benthic organisms. Pundamilia
nyererei is one of the most specialized suction feeders among rock cichlids, its diet
being zooplankton and insect larvae. A morphological analysis showed that the three
Neochromis species are better adapted anatomically to biting than P. nyererei,
-->while P. nyererei is better adapted to suction feeding. Feeding performance was tested
on algal substitute and Chaoborus larvae, representing filamentous algae and zooplankton,
respectively. As expected the Neochromis species fed most efficiently on algal
substitute, N. rufocaudalis and N. omnicaeruleus taking per bite 2·6 times as
much as P. nyererei, and N. greenwoodi 1·7 times. Unexpectedly, the species
examined were all well able to collect Chaoborus. P. nyererei collected
only 1·2 times as many larvae per suction act as the Neochromis species. Analysis of
the stomach contents showed that P. nyererei punctured, or lacerated, the larvae with
the pharyngeal jaws, while the Neochromis species swallowed them mostly intact. Thus,
feeding on Chaoborus P. nyererei may be optimizing energy gain and not intake rate.