Bubble Coral

Details

Plerogyra sinuosa, commonly called the bubble coral, is a photosymbiotic reef‑building coral in the familyEuphylliidae. By day the surface is covered with inflated, translucent vesicles (“bubbles”); at night the vesicles deflate and the colony extends feeding tentacles. It hosts Symbiodiniaceae, gaining most energy from photosynthesis and supplementing with suspended particulates/zooplankton.

Ecology & Biology

• Diel morphology: daytime inflation increases light capture and shields the skeleton; at night the bubbles retract and tentacles feed actively.

• Nutrition: primarily photosynthesis with particle/zooplankton capture via mucus and tentacles.

• Reproduction: sexual broadcast spawning/planulation and asexual budding/fission; careful fragmentation is possible in aquaculture.

Identification

Colonies are usually massive/lobate and spread along the substrate. Bubbles are pearly white to beige or pale green. At night, the sinuous septa/valleys of the skeleton become apparent. Superficially similar to Physogyra lichtensteini, but Plerogyra typically has rounder vesicles and more continuous valley ridges; definitive ID may require skeletal inspection.

Colony size & Longevity

• Colony size: commonly 15–40 cm; up to 60+ cm under favourable conditions.

• Vesicle size: typically ~0.5–2 cm diameter, varying with light and flow.

• Life: long‑lived reef builder; multi‑year to decades on stable reefs.

Range & Habitat

Widespread in the tropical Indo‑Pacific on reef slopes, leeward/back‑reef faces and cave mouths with moderate light and low–moderate flow, typically at ~5–30 m depth; sensitive to harsh direct light and heavy sedimentation.

Threats & Conservation

• Thermal stress & bleaching from elevated sea temperatures.

• Sedimentation/pollution that smother vesicles and reduce photosynthesis.

• Physical damage from anchoring, trampling and improper handling/high‑flow in aquaria.

IUCN: sources vary; to maintain consistency here we mark it as Not Evaluated (NE). Priorities: protect key reef tracts, manage nutrients/sediments and regulate trade/transport.