This hard coral with relatively neat hexagonal corallites is among
the few hard corals more regularly seen on our northern shores. They
are also seen on our southern shores. According to Veron, they are
found in very shallow water attached to bare rock and are considered
uncommon and cryptic. The genus has only one species.
Features: Colonies seen 5-10cm.
The colony is generally encrusting or a smooth dome-shape, but somewhat
irregular and not perfectly spherical. The corallites (1-1.5cm) have
shared walls and form irregular, wide, shallow cells with sharp angular
edges of various sizes and shapes. The corallites are conical with
a small 'base' and regular 'grooves' radiating from the centre. The
result is a rather neat pattern of polygons. The walls are distinctively
white. The polyp has short tentacles. Colours seen include dark green
Sometimes confused with Honeycomb
favid corals (Family Merulinidae) which have more tubular corallites
that have a broader 'base'. Leptastrea purpurea and Leptastrea
transversa may also appear similar.
Status and threats: This coral
is listed as globally 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
*Species are difficult
to positively identify without close examination.
On this website, they are grouped by external features for convenience of
hexagonal corals on Singapore shores
Pulau Ubin, Jul 17
Photo shared by Abel Yeo on facebook.
Siderastreidae 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
in red are those listed as threatened on the IUCN global list.