Green Bubble Coral

Bubble Coral (Plerogyra sinuosa) gets its name from the grape-like, fluid-filled sacs it inflates during the day to maximize surface area for its symbiotic zooxanthellae, then deflates at night to expose long sweeper tentacles used for feeding and for stinging anything that drifts too close. That inflate-and-deflate cycle is worth understanding before placement — it needs genuine breathing room, because those nighttime tentacles reach considerably further than the deflated skeleton suggests, and they carry a real sting that will damage neighboring corals.

In terms of difficulty, Bubble Coral sits at the more forgiving end of the LPS spectrum. It tolerates a real range of lighting and doesn't demand the same precision as SPS, but it does have a few non-negotiable requirements: low to moderate direct flow (too much and the bubbles won't inflate properly, which is both a visual and a biological problem), stable alkalinity and calcium, and enough space that it can expand fully without touching neighbors. Bottom to mid-tank placement on sandy substrate or stable rock suits it well.

Feed it at night when the sweeper tentacles are extended — small pieces of frozen meaty food placed near the tentacles will be captured and transferred to the central mouth.

Scientific name: Plerogyra sinuosa
Origin: Indo-Pacific — sheltered reef slopes, lagoon walls, and semi-turbid environments at 10–30m depth
Water parameters: Temp 74–82°F · Salinity 1.023–1.026 · pH 8.1–8.4 · Alkalinity 8–11 dKH · Calcium 380–450 ppm
Tank requirements: 30 gal minimum; bottom-to-mid tank placement with several inches of clearance from neighbors
Lighting: Low to moderate — metal halide or LED at low intensity; too much light causes bubbles to retract
Flow: Low to gentle — direct high flow prevents proper bubble inflation
Diet: Photosynthetic; target-feed meaty foods at night when sweeper tentacles are extended
Husbandry note: A Bubble Coral that isn't inflating its bubbles during the day is telling you something is wrong — first check flow (usually too high) and lighting (usually too intense). Stable water chemistry and low-turbulence placement are the two levers that matter most.