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Seaweeds > Division Chlorophyta > Family Halimedaceae > Genus Halimeda
Big coin green seaweed
Halimeda sp.*
Family Halimedaceae
updated Oct 2016
Where seen? This seaweed with large flat coin-like shapes are seen on many of our shores, especially on our Southern shores. Usually growing on coral rubble or among living corals. May sometimes form large 'meadows' on sandy areas near reefs.

Features: An upright chain (5-10cm long) of joined up coin-like flattened segments. Each coin-like segment is hard as it is impregnated with calcium carbonate. Big coin green seaweeds have larger segments about 2cm in diameter. The segments are thin and relatively smooth and unwrinkled. The segments may sometimes be curved into a spoon-shape. In some, clusters of these chains are held up on a stalk that is buried. Colours range from light green to bluish green. The segments of big coin green seaweeds are lightly calcified and thus are not as stiff as segments of some smaller coin green seaweed species.

Living on halimeda: The keen-eyed observer may spot the tiny Halimeda slugs (Elysiella pusilla) found on this seaweed. The slugs are difficult to spot as they usually the same colour as the seaweed or somewhat translucent.

During one visit to Tuas in Sep 08, a large stretch (about 20m) of shore at the low water mark was thickly covered with this seaweed. The seaweeds grew to about 10-15cm tall. The thickets of stiff seaweeds seemed to provide shelter for a wide variety of animals and were overgrown with a variety of encrusting organisms.

Large stretch of shore covered
with this seaweed.
Tuas, Sep 08

Sisters Islands, Jan 06

St. John's Island, May 06

Labrador, Mar 05

A pair of slugs on the seaweed.

Sentosa, Jun 04

*Species are difficult to positively identify without close examination of internal parts.
On this website, they are grouped by external features for convenience of display

Big coin green seaweeds on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Terumbu Pempang Tengah, Jun 20
Photo shared by Dayna Cheah on facebook.

Raffles Lighthouse, Jul 06

Pulau Pawai, Dec 09

Pulau Senang, Jun 10

Terumbu Berkas, Jan 10

Pulau Pawai, Dec 09



  • Lee Ai Chin, Iris U. Baula, Lilibeth N. Miranda and Sin Tsai Min ; editors: Sin Tsai Min and Wang Luan Keng, A photographic guide to the marine algae of Singapore, 2015. Tropical Marine Science Institute, 201 pp.
  • Pham, M. N., H. T. W. Tan, S. Mitrovic & H. H. T. Yeo, 2011. A Checklist of the Algae of Singapore, 2nd Edition. Lee Kong Chian Natural History Museum, National University of Singapore, Singapore. 99 pp. Uploaded 1 October 2011. [PDF, 1.58 MB].
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