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worms > Phylum Annelida > Class Polychaeta
Giant reef worm
Eunice aphroditois*
Family Eunicidae
updated Jan 2020

Where seen? This magnificent worm can be commonly encountered on our Southern shores among living and dead corals. The first encounter with this enormous worm can be disconcerting, to put it mildly. It looks much like an impossibly huge and scary centipede! But it is shy and will hide at the slightest sign of danger, and is more active at night.

What are giant reef worms? They are segmented worms belonging to the Family Eunicidae, Class Polychaeta, Phylum Annelida. The polychaetes include bristleworms, and Phylum Annelida includes the more familiar earthworm. Eunicid worms are commonly encountered on all our shores. They range from tiny ones only 1cm or shorter but include some of the longest polychaetes. Some members of Family Eunicidae can reach 6m with more than a thousand segments! These worms can live for several years. Most Eunicids are carnivorous. Some live in tubes, others may live in rocky habitats, burrow into coralline rock or limestone, or burrow into sand and mud.

A face that only a mother could love.

Sentosa, Sep 08
Features: The giant reef worm can reach up to 1.5m. Indeed, such long ones are commonly encountered on our shores. It has a white ring around the fourth body segment, short pointed bristles on the sides of the body, and long tentacles and other gruesome-looking appendages on its head. Although it does have a face that only a mother could love, it is beautiful in some ways: with glistening iridescent body segments.

Young giant reef worms crawl about freely, but as they get older, they make a simple papery tube to live in. Giant reef worms live among living hard corals as well as coral rubble.

Grabbing a piece of Sargassum seaweed.
St John's Island, Feb 11

Snatching a mouthful of seaweed.
Sisters Island, Apr 04
What does it eat? It appears to eat seaweed. It creeps cautiously out of its hiding place then quickly snatches a mouthful before retracting back instantly. Among the seaweeds we have observed being gathered by the worm include: Hairy green seaweed (Bryopsis sp.) and Sargassum seaweed (Sargassum sp.). Although it seems to have ferocious jaws, these are probably used more to ensure a good grip on the food item. They have not been observed eating animals.

But it is listed among the dangerous animals on our shores as it can give a nasty bite. So do leave the worm alone.

Pulau Tekukor, Jan 10

A young worm?
Sisters Island, Jan 12

Giant reef worm (Eunice aphroditois)

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

Giant reef worms on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Changi Loyang, May 21
Photo shared by Jianlin Liu on facebook.

Tanah Merah, May 14
Photo shared by Loh Kok Sheng on his blog.

Labrador, Aug 17
Photo shared by Jianlin Liu on facebook.

Sentosa Serapong, Jul 21
Photo shared by Vincent Choo on facebook.

Terumbu Selegie, Jun 11
Photo shared byJames Koh on his blog.

Kusu Island, Aug 07
Photo shared by Loh Kok Sheng on his blog.

Lazarus Island, Nov 19
Photo shared by Jianlin Liu on facebook.

Lazarus Island, Jun 09
Photo shared by Liana Tang on her blog.

Terumbu Buran, Jan 11
Photo shared by Loh Kok Sheng on flickr.

Cyrene Reef, Jun 09
Photo shared by James Koh on his blog.

Terumbu Pempang Laut, Apr 11
Photo shared by Rene Ong on facebook.

Terumbu Pempang Tengah, Jun 20
Photo shared by Kelvin Yong on facebook.

Pulau Semakau North, Jul 15
Photo shared by Loh Kok Sheng on facebook.

Terumbu Raya, Mar 16
Photo shared by Marcus Ng on facebook.

Terumbu Semakau, Jun 18
Photo shared by Richard Kuah on facebook.

Terumbu Salu, Jan 10
Photo shared by Loh Kok Sheng on his flickr.

Terumbu Berkas Besar, Jan 10
Photo shared by Loh Kok Sheng on his flickr.

With grateful thanks to Leslie H. Harris of the Natural History Museum of Los Angeles County for comments about these worms.


  • Gopalakrishnakone P., 1990. A Colour Guide to Dangerous Animals. Venom & Toxin Research Group, Faculty of Medicine, National University of Singapore. 156 pp.
  • Edward E. Ruppert, Richard S. Fox, Robert D. Barnes. 2004.Invertebrate Zoology Brooks/Cole of Thomson Learning Inc., 7th Edition. pp. 963
  • Pechenik, Jan A., 2005. Biology of the Invertebrates. 5th edition. McGraw-Hill Book Co., Singapore. 578 pp.
  • Jones, R.E. (Ed.) et al. 2000. Polychaetes and Allies: The Southern Synthesis Australian Biological Resources Study, Canberra. 465pp.
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