Fire Coral

Millepora dichotoma is a colonial hydrozoan that forms upright, blade-like or branching calcium carbonate structures, despite its common classification alongside "corals" in reef ecosystems. Unlike true stony corals, it belongs to Class Hydrozoa and possesses stinging nematocysts potent enough to cause painful reactions on contact, giving rise to its common name. The colony surface is dotted with tiny pores from which specialized polyps extend to capture zooplankton and other small prey.

Ecologically, it contributes to reef framework structure, providing habitat complexity that supports associated invertebrates and fish.

The species occurs across the Indo-Pacific, with records spanning Papua New Guinea, the Philippines, the Solomon Islands, American Samoa, Madagascar, Micronesia, Australia, Indonesia, Thailand, Vietnam, Yemen, Taiwan, Japan, and Guam. It inhabits shallow marine neritic waters, typically on reef flats and slopes where light penetration supports its symbiotic algae.

Its population is in decline due to a combination of pressures. Fishing and harvesting activities damage reef substrates it depends on, while disease outbreaks and interactions with problematic native species add further stress. Habitat shifting and alteration, linked to broader reef degradation, continue to erode suitable colonization sites, and unspecified pollution sources compound these effects.

Conservation responses are largely embedded within broader coral reef protection frameworks, including marine protected areas across parts of its range and international monitoring under IUCN Red List assessments. Species-specific management remains limited.

Given ongoing habitat degradation and the compounding effects of disease and human extraction pressures, the species' trajectory remains negative, consistent with its current Endangered classification and documented decreasing population trend.