Invertebrate · Stinging · Hard corals

Purple-Polyp Alveopora

Alveopora viridis Quoy & Gaimard, 1833
colonies up to 50 cm3-30 mCITES IICritically Endangered
928

You will not see the skeleton. This coral keeps its polyps out around the clock, and they are long enough and packed closely enough that the colony reads as a field of soft fingers rather than as stone. Put a hand near it and the whole surface withdraws at once, and what is left underneath is a startlingly light, porous skeleton with almost nothing solid to it.

Count the tentacles and you have named the genus. Twelve, in a neat ring around a flat mouth disc, means Alveopora. Twenty-four, on a longer stalk, means Goniopora, which grows alongside it and is mistaken for it constantly. Nothing else on the reef looks like either.

The porous skeleton is the trade-off that shapes the animal. It builds cheaply and quickly for the weight, so these corals do well on soft, silty, shaded ground where the heavy reef-builders struggle, and badly in surf, where a colony can simply break apart.

The polyps carry symbiotic algae like most corals here and get the bulk of their food from them, catching plankton on the side. In this colony the tentacle crowns are violet against a cream body, which is a color form: the same species elsewhere in its range is the green the name refers to.

How to recognise it
  • surface completely hidden under soft polyp columns, extended day and night
  • each polyp a pale fleshy tube ending in a crown of twelve short tentacles
  • tentacle crowns violet here, though the species runs green to cream elsewhere
  • colonies rounded, lobed or columnar
  • colonies up to about 50 cm

Why it's threatened

Residential & commercial development
Housing & urban areas · Commercial & industrial areas · Tourism & recreation areas
Transportation & service corridors
Shipping lanes
Biological resource use
Unintentional effects: (subsistence/small scale) [harvest] · Motivation Unknown/Unrecorded
Human intrusions & disturbance
Recreational activities
Invasive species, genes & disease
Unspecified species · Named species
Pollution
Type Unknown/Unrecorded · Soil erosion, sedimentation · Ozone
Climate change & severe weather
Temperature extremes · Storms & flooding

Species in the genus Montipora are susceptible to bleaching. Species in the genus tend to be quite fast growing and reproduce asexually by fragmentation, so if they can re-establish after mortality, they can recover fast.

In general, the major threat to corals is global climate change, in particular, temperature extremes leading to bleaching and increased susceptibility to disease, increased severity of ENSO events and storms, and ocean acidification.

Crown-of-thorns starfish (COTS) (Acanthaster planci) are found throughout the Pacific and Indian Oceans, and the Red Sea. These starfish are voracious predators of reef-building corals, with a preference for branching and tabular corals such as Acropora species. Populations of the crown-of-thorns starfish have greatly increased since the 1970s and have been known to wipe out large areas of coral reef habitat. Increased breakouts of COTS has become a major threat to some species, and have contributed to the overall decline and reef destruction in the Indo-Pacific region. The effects of such an outbreak include the reduction of abundance and surface cover of living coral, reduction of species diversity and composition, and overall reduction in habitat area.

Coral disease has emerged as a serious threat to coral reefs worldwide with increases in numbers of diseases, coral species affected, and geographic extent (Ward et al. 2004, Sutherland et al. 2004, Sokolow et al. 2009). Outbreaks of coral diseases have damaged coral reefs worldwide with the most widespread, virulent, and longest running coral disease outbreak currently occurring on the Florida Reef Tract and throughout the Caribbean. The disease, stony coral tissue loss disease, has been ongoing since 2014 (Precht et al. 2016) and has devastated affected reefs along Florida (Walton et al. 2018, Williams et al. 2021) and throughout the Caribbean (Alvarez-Filip et al. 2019, Kramer et al. 2019). Numerous disease outbreaks have also occurred in the Indo-Pacific (Willis et al. 2004, Aeby et al. 2011; 2016), Indian Ocean (Raj et al. 2016) and Persian Gulf (Howells et al. 2020). Escalating anthropogenic stressors combined with the threats associated with global climate change of increases in coral disease, frequency and duration of coral bleaching and ocean acidification place coral reefs in the Indo-Pacific at high risk of collapse.

Localized threats to corals include fisheries, human development (industry, settlement, tourism, and transportation), changes in native species dynamics (competitors, predators, pathogens and parasites), invasive species (competitors, predators, pathogens and parasites), dynamite fishing, chemical fishing, pollution from agriculture and industry, domestic pollution, sedimentation, and human recreation and tourism activities. The severity of these combined threats to the global population of each individual species is not known.

Threat classification from the IUCN Red List.

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Last Update: August 17, 2026