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| hard corals text index | photo index |
| Phylum Cnidaria > Class Anthozoa > Subclass Zoantharia/Hexacorallia > Order Scleractinia > Family Oculinidae |
| Galaxy
corals Galaxea sp.* Family Oculinidae updated Oct 11 Where seen? These small hard corals with tall, distinctive star-shaped corallites are commonly seen on many of our Southern shores. From Danwei's paper, the species found on many of our shores is Galaxea fascicularis. Features: Colonies seen 10-20cm. Colonies are rounded and small, forming irregular boulders and mounds. Polyps and corallites about 1cm in diameter. Corallites made up of long tubes joined near the tips of the tube with a common skeleton that is smooth. The corallites are tipped with a distinctive star-shape pattern that resembles a crown. The walls are thin and the skeleton is quite fragile. The polyps have short thin tentacles often with white tips. The skeleton is covered by a very thin layer of tissue. 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 blue, green, purple, brown or reddish. 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 populations. |
 Sisters Island, Jun 07   |
 Long sweeper tentacles Pulau Semakau, Sep 05 |
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Galaxy corals on Singapore shores
 Kusu Island, May 07 |
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 Pulau Hantu, Aug 03 |
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 Pulau Hantu, Jan 10 |
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more photos of galaxy corals on Singapore shores
northern shores
southern shores part 1 | part 2 | part 3 | part 4 | part 5 | part 6 | part 7 | part 8 | part 9 | part 10
*Species
are difficult to positively identify without close examination.
On this website, they are grouped by external features for convenience of display.
On this website, they are grouped by external features for convenience of display.
| Family
Oculinidae recorded for Singapore from 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 Danwei's paper. in red are those listed as threatened on the IUCN global list.
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Links
References
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Australian Institute of Marine Science, Australia. 3 volumes.
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