Bubble Coral Care Guide

Bubble Coral deflates and remains retracted when exposed to excessive water flow, which is the most common cause of deflation in aquarium settings. The coral's vesicles naturally inflate during daytime hours to maximize light absorption and deflate at night when feeding tentacles emerge, so deflation after lights-out is normal behavior. Excessive lighting intensity, poor water quality parameters, or physical disturbance from fish or invertebrates can also cause stress-related deflation during the day.

Reef keepers should verify water flow is low and indirect, with bubbles showing gentle movement rather than constant retraction, and consider reducing lighting intensity if the coral fails to inflate within 2-3 hours of lights-on. If all parameters are correct and the coral remains deflated for multiple days, test alkalinity, calcium, and magnesium levels as this species is sensitive to parameter instability.

Bubble Coral (Plerogyra sinuosa) produces aggressive sweeper tentacles extending 3-4 inches from the colony base primarily at night, delivering powerful stings capable of damaging or killing neighboring corals. These sweeper tentacles can also sting human flesh during handling or maintenance. Reef keepers should maintain a minimum of 4-6 inches of clear space around Bubble Coral colonies to prevent contact with sweeper tentacles, though individual colonies may extend tentacles beyond this range when threatened or competing for space.

Placing Bubble Coral on isolated rockwork or the sand bed away from other specimens provides the safest arrangement. While some aquarists successfully keep Bubble Coral colonies near each other without aggression, this species will sting unrelated coral species including other LPS corals.

Bubble Coral performs best when placed on the sand bed at the bottom of the reef aquarium or on flat, stable low rockwork in areas receiving moderate lighting of 100-150 PAR. The coral becomes top-heavy when its vesicles inflate during the day, creating risk of toppling if placed on tall or unstable rockwork, and the weight of water-filled vesicles can cause the colony to tumble and damage its fragile tissue. Placement should account for low, indirect water flow with visible gentle movement of the vesicles rather than strong direct current that causes deflation.

The coral's skeleton should not contact sharp rock edges that can chafe and tear the vesicles as they inflate. Bubble Coral requires 4-6 inches of clear space from neighboring corals to prevent sweeper tentacle contact at night, making lower tank positions ideal where aggressive tentacles have room to extend without reaching nearby specimens.

Bubble Coral (Plerogyra sinuosa) is photosynthetic and obtains up to 90% of its energy from symbiotic zooxanthellae living within its tissues, but target feeding enhances growth rate, coloration, and long-term health. Reef keepers should offer weekly feedings of mysis shrimp, brine shrimp, or finely chopped seafood using a turkey baster or pipette to gently deliver food directly onto the coral's vesicles, which will part to reveal the mouth and consume the offering. Feeding 2-3 times per week promotes faster growth and more vibrant colors compared to light-only nutrition.

The coral's feeding behavior is most active at night when the vesicles deflate and sweeper tentacles emerge to capture food, though daytime target feeding works when food is placed directly on the bubbles. Bubble Coral will capture zooplankton-sized foods that drift into contact with feeding tentacles, supplementing deliberate target feeding efforts.

Bubble Coral (Plerogyra sinuosa) is an intermediate-level coral requiring specific care conditions and is not recommended for beginning reef keepers despite some sources describing it as beginner-friendly. The species is sensitive to water flow levels, deflating permanently if exposed to excessive current, and requires careful placement on stable substrate to prevent toppling when vesicles inflate. Bubble Coral's fragile vesicles rupture easily when the coral is removed from water or handled roughly, and the species tends to struggle with long-term survival in captivity without proper care including stable water parameters, appropriate lighting acclimation, and regular feeding.

Beginning aquarists will find more success with hardy LPS corals like Goniopora or Euphyllia species that tolerate wider parameter ranges and higher flow. Experienced reef keepers who can provide low indirect flow, moderate stable lighting, and patient acclimation will have better success maintaining healthy Bubble Coral colonies.

The terms "bubble coral" and "pearl coral" are often used interchangeably in the aquarium trade, though they can refer to different species with distinct characteristics. Plerogyra sinuosa, commonly called bubble coral, features larger grape-sized vesicles up to 1 inch in diameter and a blade-like skeletal structure. Physogyra lichtensteini, often marketed as pearl coral or pearl bubble coral, displays smaller pearl-sized vesicles and a flatter skeleton compared to Plerogyra species.

Both genera belong to the family Euphyllidae and share similar care requirements including moderate lighting and low flow, though Physogyra's smaller vesicles may tolerate slightly higher flow without deflating. Many retailers use "bubble coral" and "pearl coral" as common names for both species without species-level identification, making visual identification the primary method for distinguishing between larger-bubbled Plerogyra and smaller-bubbled Physogyra varieties.