worms text index | photo index
many different Phyla
Marine worms
updated Oct 2016
if you learn only 3 things about them ...
Not all worms are worm-like; not all worm-like creatures are worms!
Some can bite or sting. Others are fragile. Don't touch!
They can be quite colourful and beautiful.

Almost everyone knows what a worm looks like. But the worms on our shores can look very different from the worms we are more familiar with. They are found in all kinds of marine habitats.

What is a worm?
An animal with a soft body that is much longer than it is wide is usually called a worm. Although they may appear similar, worms may belong to very different Phyla, often with quite different internal structures.

Beautiful Worms: Some worms may appear totally unworm-like. Fan worms (Family Sabellidae, Phylum Annelida), for example, look more like flowery creatures. So do the small Phoronid worms (Phylum Phoronida) that often live with Peacock anemones.

Others such as flatworms (Phylum Platyhelminthes) look like frilly, flat ovals and come in a delightful variety of colours and patterns. Even 'typical worms' can be appealing. Some bristleworms (Class Polychaeta, Phylum Annelida) are enchantingly iridescent and may come in shades of pink, red and green. They are sometimes seen under stones or moving about in the sand and mud.

Living in a tube:
Many worms make tubes to protect their soft bodies against predators and drying out. In undisturbed shores, tubeworms riddle the ground leaving only a tiny bit of their tubes sticking out to the surface. Keelworms (Phylum Annelida) build hard tubes out of calcium carbonate and are common under stones.

Unseen worms: Some amazing worms are rarely seen although they are common. The strange Peanut worm (Phylum Sipuncula) is sometimes seen above ground. The Acorn worm (Phylum Hemichordata) is almost never seen outside its underground tunnel. But the grey coils of sediment (called the cast) that it leaves on the surface are often encountered on the sand bar.

Some worms can be very long! These include the amazing Ribbon worms (Phylum Nemertea) that can be more than 1m long! The Giant reef worm (Eunice aphroditois) is also very long and scary-looking!

But there are countless different types of microscopic worms. New ones are constantly being discovered.

Not worms! There are also other creatures that look like worms but are not correctly called worms. These include:

Synaptid sea cucumbers: These soft worm-like creatures are actually Echinoderms like sea stars! Nudibranchs and other slugs are snails without shells that belong to the Phylum Mollusca. While Vermetids look like worms that live in calcareous tubes, they are actually snails!

Even some fishes like the Worm eel (Family Ophichthidae) is sometimes mistaken for a worm; while small flatfishes are sometimes mistaken for flatworms. Here's more about how to tell apart worm-like animals.

A beautiful bristleworm
Raffles Marina, Apr 05

Fan worms
Phylum Annelida

Phoronid worms
Phylum Phoronida

Phylum Platyhelminthes

Phylum Platyhelminthes

Peanut worm
Phylum Sipuncula

Ribbon worm
Phylum Nemertea

Giant reef worm
Phylum Annelida

Phylum Annelida

Acorn worm
Phylum Hemichordata

Marine worms on Singapore shores
text index and photo index of marine worms on this site

Threatened marine worms of Singapore
from Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore.

Phylum Platyhelminthes flatworms
  Family Polycladida
  Meixneria furva (DD: Data deficient)

Phylum Nemertea ribbon worms
  Family Geonemertidae
  Pantinonemertes sp. (EN: Endangered)

Phylum Annelida, Class Polychaeta bristleworm
  Family Chaetopteridae
  Chaetopterus variopedatus (EN: Endangered)



  • Davison, G.W. H. and P. K. L. Ng and Ho Hua Chew, 2008. The Singapore Red Data Book: Threatened plants and animals of Singapore. Nature Society (Singapore). 285 pp.
  • Gosliner, Terrence M., David W. Behrens and Gary C. Williams. 1996. Coral Reef Animals of the Indo-Pacific: Animal life from Africa to Hawaii exclusive of the vertebrates Sea Challengers. 314pp.
  • Allen, Gerald R and Roger Steene. 2002. Indo-Pacific Coral Reef Field Guide. Tropical Reef Research. 378pp.
  • 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.
  • Newman, Leslie and Lester Cannon. 2003. Marine Flatworms: The World of Polyclads. CSIRO Publishing. 97pp.
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