Ecology

E. obtusa utilise siphonaceous green algae as a food source, as both the direct nourishment from the cytoplasm of the prey, and through the retention of chloroplast through kleptoplasty (Brandley 1984). As such, the animals would be expected to be found in areas of the reef with algae present that are also sheltered, as E. obtusa are not strong swimmers and tidal action or currents may remove them from their habitat and food source. There must also be suitable amounts of light to sustain the algae on which they feed and kleptoplasty if required.