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Phylum Cnidaria > Class Anthozoa > Subclass Alcyonaria/Octocorallia > Order Pennatulacea
Flowery sea pen
Family Veretillidae*
updated Dec 2019
Where seen? This beautiful colony of flowery polyps is often seen on our Northern shores, mainly at night. On soft silty sand among seagrasses.

Features: Colony 15-20cm long. Long, sausage-like 'stem', called the axial or primary polyp, that supports the whole colony. No leaf-like structures. Feeding polyps (autozooids) large (1-2cm) with eight branched tentacles emerge directly evenly from and all around the 'stem'. Tentacles usually white, but the body column may match the colour of the 'stem'. Colours seen include white, maroon, purple and orange. The colony also has another kind of polyp that sucks in water (siphonozooids) and which are minute, numerous and crowded.

Changi, May 05

Autzooids with long columns
and eight branched tentacles.
The bottom half of the primary polyp forms a muscular 'foot' (called the peduncle) that anchors the colony and retracts the whole colony into the ground at low tide. This portion lacks other kinds of polyps. The central stalk is usually stiffened by an internal 'bone' made of calcium.

When exposed at low tide, the autozooids can retract completely and the fat central stalk flops over so that it looks like a limp sausage on the sand.

Sometimes confused with other sausage-shaped animals. Here's more on how to tell apart sausage-shaped animals.

'Uprooted' flowery sea pen showing 'foot' that is usually buried, and stiff internal 'bone'.
Beting Bronok, Jun 21

May look like a 'sausage'.
Pasir Ris Park, Oct 20
Pen pals: Sometimes, tiny transparent shrimp may be seen among the tentacles of the sea pen. The shrimps are often found in pairs and often all you can see of them are their eyeballs!

A nudibranch that eats sea pens
is lurking near this one.
Changi, Aug 14

Commensal shrimp on the sea pen.
All that can often be seen are a pair of eyes!
Changi, May 05

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

Flowery sea pens on Singapore shores
On wildsingapore flickr

Other sightings on Singapore shores

Coney Island, Apr 19
Photo shared by Richard Kuah on facebook.

Coney Island, Oct 20
Photo shared by Richard Kuah on facebook.

Chek Jawa, Aug 09
Photo shared by Loh Kok Sheng on flickr.

An uprooted sea pen with
flowery secondary polyps retracted.
Pulau Ubin, Dec 09
Photo shared by James Koh on his blog.

Beting Bronok, May 09

Changi, Jun 05

Pulau Sekudu, May 10



  • Erhardt, Harry and Daniel Knop. 2005. Corals: Indo-Pacific Field Guide IKAN-Unterwasserachiv, Frankfurt. 305 pp.
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