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Phylum Cnidaria > Class Anthozoa > Subclass Zoantharia/Hexacorallia > Order Scleractinia > Family Oculinidae
Galaxy corals
Galaxea sp.*
Family Oculinidae
updated Feb 09

Where seen? These small hard corals with tall, distinctive star-shaped corallites are commonly seen on many of our Southern shores.

The Family Oculindae includes the genera Galaxea recorded in Singapore. Members of the family generally have corallites made up of long tubes joined near the tips of the tube with a common skeleton that is smooth.

Features: Colonies seen 10-20cm. Colonies are rounded and small, forming irregular boulders and mounds. Polyps and corallites about 1cm in diameter. The corallites are long with a distinctive star-shape pattern at the tips. 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 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: None of our galaxy corals are listed among the endangered animals of Singapore. However, 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

Galaxy corals on Singapore shores


Kusu Island, May 07


Pulau Hantu, Aug 03


Pulau Hantu, Jan 10

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


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

Family Oculinidae recorded for Singapore
from Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity in Singapore.
in red are those listed among the threatened animals of Singapore from Ng, P. K. L. & Y. C. Wee, 1994. The Singapore Red Data Book: Threatened Plants and Animals of Singapore.

  Family Oculinidae
  Galaxea cf astreata
Galaxea fascicularis

References

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