Crustal Fire Coral
CR

Crustal Fire Coral

Millepora squarrosa

Declining

Photo: Photo: Wikimedia Commons, CC BY-SA

Overview

Millepora squarrosa is a species of fire coral that can be found in the Caribbean Sea as well as in the western Atlantic. They are very common on fringing reefs in patches. They have a smooth surface covered in tiny pores from which polyps protrude.

They can reach up to 5 centimeters in height and can range from brown or tan in color with slight purple or red tints. It is commonly known as "box fire coral", which refers to its box-like structure and the stinging sensation felt when touched with a bare hand. These corals are important to reef-building.

Millepora squarrosa faces severe population decline primarily due to coral bleaching events triggered by rising sea temperatures and ocean acidification. The species is particularly vulnerable to mass bleaching episodes that have devastated Caribbean coral reefs, with recovery hampered by its slow growth rate and limited dispersal ability. Coastal development and pollution further stress remaining populations, while hurricane damage can eliminate entire colonies from already fragmented reef systems.

Threat summary

Habitat

Millepora squarrosa inhabits shallow tropical coral reef environments in the Caribbean, typically found in areas with strong water circulation and high light penetration. This fire coral species forms encrusting and branching colonies on reef slopes and fore-reef zones at depths ranging from 1 to 30 meters.

Marine neritic· major

Conservation measures underway

Habitat & natural process restorationSpecies recoveryEx-situ conservationLegislation

Other threatened species in MILLEPORIDAE

VU

Millepora latifolia

Declining
EN

Fire Coral

Millepora dichotoma

Declining
EN

Millepora platyphylla

Declining
EN

Millepora tenera

Declining

Threatened in Belize

EN

Baird's Tapir

Tapirus bairdii

Declining
VU

Yucatan Brown Brocket

Mazama pandora

Declining
VU

Bauhinia dipetala

Declining
VU

Blakea calycularis

Declining

Frequently asked questions

Why is Crustal Fire Coral classified as Critically Endangered?
Crustal Fire Coral is classified as Critically Endangered — facing an extremely high risk of extinction in the wild — because population sizes are very small, declining sharply, or restricted to a tiny range. Millepora squarrosa faces severe population decline primarily due to coral bleaching events triggered by rising sea temperatures and ocean acidification. The species is particularly vulnerable to mass bleaching episodes that have devastated Caribbean coral reefs, with recovery hampered by its slow growth rate and limited dispersal ability. Coastal development and pollution further stress remaining populations, while hurricane damage can eliminate entire colonies from already fragmented reef systems.
Where does Crustal Fire Coral live?
Crustal Fire Coral occurs in Belize, Brazil, Dominican Republic, and Panama. Country-level distribution data is sourced from the IUCN Red List and cross-referenced with GBIF occurrences.
What are the main threats to Crustal Fire Coral?
The main threats to Crustal Fire Coral are 11.1, 2.1, 5.4, and 6.1. The full IUCN-classified threat record for this species is detailed on the species page.

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