Bubble Coral
Plerogyra sinuosaAlso known as Grape Coral, Bladder Coral, Pearl Coral
Bubble corals dominate sheltered reef slopes with their distinctive, water-filled vesicles that swell to the size of grapes under daylight. These specialized structures act as protective cushions and house photosynthetic algae, then deflate at dusk to allow long, venomous tentacles to sweep the night currents for plankton. Their fragile skeletons and slow growth make them vital but sensitive structural pillars of Indo-Pacific coral communities.
- diet
- Plankton, organic particles, and symbiotic sugars from zooxanthellae
- family
- Plerogyridae
- threats
- Coral bleaching, ocean acidification, and unsustainable harvesting for the aquarium trade
- life Span
- Decades to centuries
NT
Possesses potent stinging tentacles that can damage neighboring corals and irritate human skin; avoid touching.
Deploys long sweeper tentacles armed with powerful nematocysts (stinging cells) at night to defend territory.
Never touch the delicate tissue or get too close at night when stinging tentacles are extended.Highly vulnerable to rising sea temperatures, which trigger bleaching, and localized over-harvesting for aquariums.
Avoid anchoring boats nearby or kicking up sediment, which smothers the delicate polyps.- Observe the shift: Watch how the grape-like vesicles deflate at night to reveal long, translucent feeding tentacles.
- Maintain distance: Keep hands and camera gear away to prevent damaging the fragile, water-filled bubbles.
- Look in crevices: Search for them under overhangs and in sheltered reef areas where water currents are gentle.