Description

Also known as Cloak Anemone, Hexacoral, Outer-hermit Sea Anemone.

Found on the Anemone Hermit Crab - Dardanus pedunculatus, or on other sea snail shells. The crab or sea snail acts as its host, and in return provides protection from predators, found over coral and rocky reefs.
They feed on plankton.
Length - 8cm
Depth - 0-25m
Widespread Indo-Pacific

Usually found on the Anemone Hermit Crab - Dardanus pedunculatus.
http://www.whatsthatfish.com/fish/anemone-hermit-crab/175
When Hermit crabs need to change their shells, they do so at night and at the same time move their anemones from their old homes to the new!

Sea Anemones are large solitary polyps which have no skeleton. They have a basal or pedal disc which helps them crawl and dig into place, for some, once in place it is virtually impossible to move. Other smaller anemones move around the reef to feed at night.
Most eat plankton, but they are capable of eating anything caught in their stinging tentacles including quite big fish.
The fringing tentacles are configured in six or multiples of six.
Some sea anemones have a symbiotic relationship with sea anemones and some live commensally with various crabs, shrimp and brittle stars. (edit) Ref: https://en.wikipedia.org/wiki/Calliactis_polypus