starry cup coral

Acanthastrea hemprichii is a reef-building coral characterized by fleshy, meaty-textured polyps arranged in large, rounded to encrusting colonies, often displaying vivid coloration including greens, reds, and mottled patterns across their corallites. Like other scleractinian corals, it secretes a calcium carbonate skeleton that contributes to the physical structure of reef systems, providing habitat complexity for numerous fish and invertebrate species. It relies on a symbiotic relationship with photosynthetic zooxanthellae housed within its tissues, which supply the majority of its energy needs, while the coral itself supplements feeding by capturing plankton and organic particles at night.

This species has a broad Indo-Pacific and western Indian Ocean distribution, occurring in countries including Australia, Japan, Indonesia, Vietnam, Madagascar, Egypt, Saudi Arabia, Oman, and numerous Pacific island nations such as the Marshall Islands, Micronesia, and Tonga. It inhabits shallow marine reef environments, typically on reef slopes and in lagoon settings.

The species faces multiple compounding threats. Rising sea temperatures trigger bleaching events that disrupt the coral-algae symbiosis, while ocean acidification impairs skeletal calcification. Coastal development introduces sedimentation that smothers coral tissue and blocks light, and agricultural runoff contributes to nutrient pollution and localized water quality decline. Its attractive coloration and morphology also make it a target for collection in the aquarium trade.

Conservation efforts include its listing under CITES Appendix II, which regulates international trade, along with marine protected area designations across parts of its range and broader reef monitoring programs. Population trends remain unknown due to limited species-specific data. Given the persistence of climate-related and local stressors across its range, the long-term outlook remains uncertain, consistent with its Vulnerable classification.

Starry cup coral inhabits shallow coral reefs and lagoons in the Indo-Pacific, typically found at depths of 5-30 meters on reef slopes and protected areas with moderate water flow. It forms large colonies on hard substrates and requires clear, warm waters with stable salinity levels.