[1] The grey fan hydroid grows as a grey to dark brown fan-shaped colony that may be 40 cm in total height.

The main stem of old colonies can be quite thick and flattened in the plane of branching.

Hydranths are scattered irregularly on the stem and branches.

[2] This colonial animal is found only around the South African coast from the Atlantic side of the Cape Peninsula to KwaZulu-Natal in 10-130m under water.

[2] Gonophores (reproductive structures) are irregularly spaced on the branches and are rounded with short stalks.