Flatworms (platyhelminths) range from being conspicuous and brightly coloured free-living species to parasitic forms that spend most of their time in one or more hosts. Free-living turbellarians can be found in most coral reef habitats including inner and outer reef zones, the seaward platform, reef slope and the deeper inter-reefal zone. Parasitic forms have complex life cycles that often include a fish host and a secondary invertebrate host. There are many specific host-parasite relationships known from neodermates inhabiting Heron Island Reef and, no doubt, hundreds more to be discovered.
reef zones of the southwest end of Heron Island Reef
(Image provided by Digital Globe Inc and Biophysical Remote Sensing Group, The University of Queensland)