As a result, it has varying numbers of arms, and Hubert Lyman Clark, writing in 1938, stated, "It is a literal truth that no two of the 56 specimens at hand, nearly all from Lord Howe Island, are exactly alike in number, size and form of arms".

[3] Nepanthia belcheri is native to the Pacific coast of Australia from the Low Islands in Queensland to Port Jackson in New South Wales.

[2] It also occurs in Southeast Asia and is found under boulders and rubble where conditions are muddy, from the intertidal zone down to a depth of about 45 m (150 ft).

[2] During its second and third years, when it is actively growing and its arm length is either about 15 or 22 mm, N. belcheri can reproduce by fragmentation.

[3] Many larger individuals provide evidence from the varying lengths of their arms that they have divided by fission on several occasions.