Early this year a member of Nature Coast Marine Group, Tony Brown, photographed a strange organism on kelp at Bawley Point. It was so weird it could have been from another planet.

After many fruitless enquiries of experts in museums and on the web, the animal was finally identified. It is a rare hydroid, Candelabrum australe, known only from southern Australian and New Zealand waters.

It wasn’t until we did some research on the animal that we discovered just how strange it is. Like others in its phylum, such as anemones, corals, jellyfish and bluebottles, it has stinging cells. However, most attached hydroids are very small and solitary or in feathery colonies of tiny animals.

Candelabrum australe is a relatively large, solitary, orange-coloured hydroid. It is highly sensitive and contracts at the first sign of danger, which could include inquisitive photographers since the photo shows a contracted animal.

Our members thought it looked like a witch’s hat. The tapered “crown” is used for feeding. It can be extended from 2 to 6 cm and moved about like an elephant’s trunk so the mouth at the top can engulf prey.

This hydroid is also unusual in that it has nine different types of stinging cells all of which appear to be used for defence. Those on the “hat’s crown” are found massed together in globular ends of short tentacles. When the animal is contracted the tentacles are crowded together giving a bumpy appearance.

The base consists of short radiating tubes each ending in a circular disc. The base is hidden in the photo but attaches the animal very firmly, usually to an Ecklonia kelp frond.

Above the base is a bubbly-looking section that contains the reproductive tissues and clusters of tentacles with several different types of stinging cells.

Candelabrum is bi-sexual. The eggs and sperm develop in separate spherical sacs that are about 1mm in diameter when mature. Fertilisation and early larval development occurs in the female sacs and, when mature, often several larvae are visible. When released the flattened larvae are only capable of very slow movement so probably rely on the water to get them to a suitable piece of kelp to call home. However, once attached they can live for 3 years or more, a long time, for a hydroid.