Great Star Coral

Montastraea cavernosa

Also known as Cavernosa, Great Star, Greater Star Coral, Caribbean Star Coral

SaltwaterCoral

Great Star Coral (Montastraea cavernosa) — Nhobgood Nick Hobgood · CC BY-SA 3.0

Care at a glance

Temperature: 73–81°F (23–27°C)
pH: 8.1–8.4
Adult size: 11.8 in (30 cm)
Minimum tank: 53 gal (200 L)
Temperament: Mostly peaceful
Social behavior: Solitary
Swim level: Bottom
Difficulty: Easy
Breeding: Hard
Rarity: Common
Reef safe: Reef safe
Origin: Native to Caribbean and western Atlantic reefs, from Florida and the Gulf of Mexico through the Caribbean to Brazil.
Family: Montastraeidae

Overview

Because it grows large and slow, give it a 200 liter or larger reef with moderate light and moderate flow, mounted low where it has room to spread. Standard reef chemistry suits it, with temperature 23 to 27 C, pH 8.1 to 8.4, and stable alkalinity and calcium. Feed it at night with mysis or small meaty foods when the polyps and tentacles extend. It defends its space with sweeper tentacles that reach out after dark, so leave a clear buffer around the colony.

In the wild

A stony coral that builds heavy domes and boulders studded with round corallites the size of a thumb tip, each one a raised bump across the surface. By day it looks like a bumpy green, brown, red, or orange mound, and at night each polyp opens into a ring of tentacles that gives it a starry look. Wild colonies can grow into massive boulders several feet across. Green and orange fluorescent forms are the ones usually seen in the hobby.

Good to know

Montastraea cavernosa is the only species in the family Montastraeidae, making the genus effectively monotypic in current classification. It is a major Caribbean reef builder and a favorite subject in coral research on bleaching and fluorescence. The coral hosts zooxanthellae but feeds actively at night, extending polyps and sweeper tentacles.