The potential feeding advantages that are offered to the barred mudskipper Periophthalmus argentilineatus by its amphibious life-style were investigated. To this end the feeding ecology of these fish, the position they occupy in the mangrove food web and the importance of different morphological factors for their diet were studied. Analysis of gut contents showed that the major component of the barred mudskipper diet changes during growth from small crustaceans (e.g. copepods and amphipods) to polychaetes to mangrove crabs. This dietary shift was found to be facilitated through enlargement of the mouth, as well as elongation of the gut. The use of stable isotope analysis revealed that barred mudskippers had a similar trophic position as other zoobenthivore fish species, but that their diet did not appear to be affected by competition for food with other zoobenthivores. The amphibious habits of the barred mudskipper provide specific advantages to its feeding ecology, such as access to an abundant food source of mangrove crabs, which are mostly inaccessible for other fish species. # 2007 The Authors Journal compilation # 2007 The Fisheries Society of the British Isles