seen? These small hard corals with tall, distinctive star-shaped
corallites are commonly seen on many of our Southern shores. They used to be placed in Family Oculinidae. From
Danwei's paper, the species found on many of our shores is Galaxea
Features: Colonies (10-20cm),
elsewhere are said to reach 5m in diameter. Colonies are dome-shaped,
forming irregular boulders and mounds. Polyps and corallites about
1cm in diameter. Corallites made up of long tubes tipped with a distinctive
star-shape pattern that resembles a crown. Near the top of the long
corallites, they are joined together with a common skeleton that is
smooth. The skeleton is thin and quite fragile. The polyps have short
thin tentacles often with white tips. When fully expanded, the tentacles
hide the skeleton structure. The polyps may produce very long sweeper
tentacles (up to 30cm) that clear the surrounding area of competiting
corals and other encrusting animals. Colours seen include brown, blue,
green and purple.
Galaxy friends: The spaces among
the tubular corallites provide shelter for all kinds of animals (mussels,
crabs, shrimps) often hidden deep within the colony.
Galaxy babies: Galaxea fascicularis has a unique
method of reproducing. There are two types of colonies. One type is
a female colony that produces only red eggs. Another type is hermaphrodite
that produces sperm and white 'eggs'. The eggs are not real eggs and
help the sperm to float up to the surface where they can fertilise
the real red eggs.
Human uses: These corals are among
those taken for the live aquarium trade. They often do poorly in captivity.
They are fragile and break easily, and collection techniques usually
result in poor specimens that quickly die from disease. In addition,
their habit of producing sweeper tentacles make them poor tank-mates.
Status and threats: Galaxea
astreata is listed as globally Vulnerable and Galaxea fascicularis
as Near Threatened by
the IUCN. Like other creatures of the intertidal zone, they are
affected by human activities such as reclamation and pollution. Trampling
by careless visitors, and over-collection also have an impact on local
may form fields
of small colonies.
Pulau Hantu, Jan 10
Made of up long
corallites, joined near
the top with a smooth common skeleton.
Beting Bemban Besar, Jun 09
with distinctive star- or
crown-shaped pattern at the top.
Kusu Island, May 05
Long sweeper tentacles
Pulau Semakau, Sep 05
short slender with white tips.
Sisters Island, Apr 04
are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience
corals on Singapore shores
Jul 06 |
Tanah Merah Ferry Terminal, Jun 15
Photo shared by Loh Kok Sheng on facebook.
Jun 10. |
Photo shared by Loh Kok Sheng on his
|Galaxea species recorded for Singapore
Danwei Huang, Karenne P. P. Tun, L. M Chou and Peter A. Todd. 30 Dec
2009. An inventory of zooxanthellate sclerectinian corals in Singapore
including 33 new records **the species found on many shores in
in red are those listed as threatened
on the IUCN global list.
Galaxea fascicularis** (Near Threatened)
fascicularis on Corals of the World online on the Australian
Institute of Marine Science website: Technical fact sheet.
fascicularis on the IUCN Red List of Threatened Species
website: Technical fact sheet.
fascicularis on SeaLife Base: Technical fact sheets.
on Reef Corals of the Indo-Malayan Seas, the Marine Species Identification
Portal: Technical fact sheet.
- Danwei Huang,
Karenne P. P. Tun, L. M Chou and Peter A. Todd. 30 Dec 2009. An
inventory of zooxanthellate sclerectinian corals in Singapore
including 33 new records (pdf). Raffles Bulletin of Zoology
Supplement No. 22: 69-80.
- Veron, Jen.
of the World
Australian Institute of Marine Science, Australia. 3 volumes.
- Chou, L.
M., 1998. A
Guide to the Coral Reef Life of Singapore. Singapore Science
Centre. 128 pages.
Harry and Daniel Knop. 2005. Corals:
Indo-Pacific Field Guide
IKAN-Unterwasserachiv, Frankfurt. 305 pp.
Eric H. 2001. Aquarium
Corals: Selection, Husbandry and Natural History
T.F. H Publications. 464 pp
- Wee Y.C.
and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
National Council on the Environment. 163pp.
- Ng, P. K.
L. & Y. C. Wee, 1994. The
Singapore Red Data Book: Threatened Plants and Animals of Singapore.
The Nature Society (Singapore), Singapore. 343 pp.