Bubble Coral

About

Bubble coral (Plerogyra sinuosa) is one of the more visually distinctive large-polyp stony corals available to reef keepers, and its common name tells you exactly why. During the day it inflates a cluster of fluid-filled vesicles that look remarkably like bunches of pale grapes, typically cream or a soft bluish-grey in color. These bubbles are not just for show. They expand to maximize surface area for light absorption, and when they deflate at night, long sweeping tentacles emerge to feed. That two-phase appearance can catch newer keepers off guard the first time they see it. In the wild, Plerogyra sinuosa grows in protected reef environments, often in areas with reduced water clarity, so it tolerates moderate rather than intense lighting. It does need calm water flow. Strong currents will prevent the vesicles from inflating properly and can damage the tissue over time. The skeleton underneath is a maze-like meandroid structure, and in older colonies you sometimes see the basal skeleton partially dead while living tissue continues growing outward. Its sweeping nocturnal tentacles have decent reach and sting, so give it plenty of space away from neighbors. A reasonable choice for intermediate reef keepers who plan their tank layout carefully.