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Phlyctenactis tuberculosa (Family Actiniidae)

Buoyant Swimming Anemone



Phlyctenactis tuberculosa occurs in temperate Australia from Geraldton, Western Australia to Forster, NSW. It has also been recorded from New Zealand. (NSW, VIC, TAS, SA, WA)


Unlike most other sea anemones, the Bouyant Swimming Anemone, also known as the Wandering Beach Ball or Brain Anemone does not attach to a substrate. Rather, it drifts in the current, crawls along the bottom or swims with undulating movements of its tentacles. It is easily recognised by the numerous bladder-like vesicles bulging from the column surface, between the tentacles. When the tentacles are contracted during the day, only the vesicles are visible so that the anemone has been described as looking "like a ball of baked beans". This anemone grows to 150 mm long. The base is orange, the column brown, and the vesicles are a darker or lighter shade of orange or brown or sometimes blue-grey. The oral disc is yellow and the tentacles are yellow, grey or brown.

Ecology/Way of Life:

This species is usually found in quiet sheltered pools on rocky coasts, but does occur to a depth of 30 m. It is sometimes seen loosely attached to seagrasses or algae or washed up on beaches. It is most active at night when it actively preys upon small invertebrates.

Preferred Image

Interaction with Humans/Threats:

There are no known threats to the Buoyant Swimming Anemone.

Other Comments:

Although not a particularly abundant species, it is well represented in museum collections presumably because of its large size, unusual appearance and its tendency to be washed-up on beaches. It is a very distinct species and therefore easily identified and so is more likely to be identified within museum collections.

Further Reading:

Dakin, W.J. (1987) W.J Dakin's classic study Australian Seashores: a guide to the temperate shores for the beach-lover, the naturalist, the shore-fisherman and the student. Angus & Robertson Publishers, North Ryde. 411 pp.

Edgar, G.J. (1997) Australian Marine Life: the plants and animals of temperate waters. Reed Books, Kew. 544 pp.

Fautin, D.G. (2003) Hexacorallians of the World.

Larson, R.J. & Cooper, J.W. (1982) Phylum Cnidaria In, Walls, J.G. (ed.) Encyclopaedia of Marine Invertebrates. T.F.H. Publications, Neptune, New Jersey, pp. 66 – 133.

Thomas, I.M. & Shepherd, S.A. (1982) Sea anemones (Orders Actiniaria, Zoanthidea and Corallimorpharia) In, Shepherd, S.A. & Thomas, I.M. (ed.) Marine Invertebrates of Southern Australia Part I. Handbook of the flora and fauna of South Australia, Government Printer, South Australia. pp. 161 – 169.


Text & map by Carden Wallace & Zoe Richards, Museum of Tropical Queensland.

Photograph by Karen Gowlett-Holmes.

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Images and Multi-media:  
Attached Image  
image/jpeg 68509 bytes Phlyctenactis tuberculosa
Distribution Map  
image/jpeg 6680 bytes Distribution of Phlyctenactis tuberculosa

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