Reefs are incredibly important habitats. They provide a hard surface to which benthic organisms such as corals, kelps and sponges can attach, and once these organisms establish they provide complex 3D structures which can alter the environment by influencing factors such as water flow and the amount of light reaching the seafloor. A healthy reef ecosystem can contain thousands of different species of fish and invertebrates which are well adapted to these unique conditions, and use these habitats for shelter, foraging and recruitment grounds. This crab in the Kimberley Marine Park has made it's home inside a sponge, where it was found hiding with a host of juveniles.