Bubble Coral: Plerogyra sinuosa

Phylum: Class: Order: Family: Genus: Species:
Cnidaria Anthozoa Scleractinia Euphyllidae Plerogyra P. sinuosa

Common Names:  Bubble Coral

Scientific Name:  Plerogyra sinuosa

Veron Corals of the World:
Characters: Colonies are flabellomeandriod with valleys more or less connected by a light blistery coenosteum.  Sometimes living parts of colonies are separated by dead basal parts.  Vesicles are the size of grapes and usually have the shape of grapes but may be tubular, bifurcated or irregular, depending primarily on the state of inflation.  Color: Cream or bluish-gray  Similar species:  Plerogyra discus.  Habitat:  Protected reef environments, especially but not necessarily in turbid water.  Abundance:  Usually uncommon.

P. sinuosa are characterized by having large water filled bubbles (vesicles) typically about the size and shape of grapes.    While typically smooth, the vesicles can also look asymmetrical especially when they are only partially inflated.  The color can range from white, to cream, to shades of gray or green and is semi-translucent.  The vesicles cover a skeleton which has large sharp sepia protruding upwards.  The bubbles are inflated during the day and deflate at night.  When deflated, the feeding tentacles and mouth become apparent and the sepia can be observed under the flesh of the coral.

The related P. simplex looks similar, but the vesicles are smaller, usually the size of pearls, hence the common name of Pearl Bubble Coral.

Natural Environment:
Found over much of the West Pacific and Indian Oceans.  They typically live in protected reef environments in areas of low water flow and often in low light conditions such as under rock over-hangs.

Bubble corals are very hardy corals once they adapt to the tank environment and are tolerant of less than ideal conditions regarding lighting and to some extent water quality. When handling, care must be used to not lift the coral out of the water with the vesicles inflated or damage to the coral may result from the sepia ripping through the flesh of the coral.  You should either prod the coral to get it to retract the vesicles before lifting it out of the water or better still, keep the coral submerged in water during handling.  When selecting a specimen, look for this type of damage to the coral which may have occurred during shipment.

Bubble coral are very forgiving when it comes to lighting.  They seem to prefer low to moderate lighting, but will adapt to high intensity lighting if they are acclimated to it slowly.  They can also survive under fairly dim lighting if they are target fed on occasion to supplement their nutrition.

Water Current:
Prefers low to moderate water motion.  Slight movement of the vesicles is desirable, but if the flow is too strong, the vesicles may not inflate fully or damage to the coral may occur if the strong water currents cause the sepia to rip through the body of the coral.

Fairly high.  Bubble coral tentacles pack a fairly powerful sting and also possess sweeper tentacles that can extend up to about 2″ and which also have a powerful sting that they used to wage warfare on any close neighbors.  In a fight, the Bubble coral generally wins.

Bubble corals are photosynthetic which will take care of most of their nutritional needs, especially when placed under moderate to strong lighting.  They will also readily take any meaty foods such as Mysis shrimp or chopped fish or table shrimp and will do best with an occasional target feeding.  This is especially true in low light conditions where photosynthesis alone may not meet all of their nutritional requirements..

Supplements & Water Chemistry:
Salinity should be maintained between sg 1.024 and 1.026.
Alkalinity should be maintained in the dKH 7-12 range
Calcium should be maintained at 400 ppm or higher.
pH should be maintained between 8.1-8.4

Does well within a range of at least 74º to 84º F

Tank Positioning:
Best positioning is in low to moderate water flow, in a moderate light area of the tank either on the sand or on the rocks.  If you have rock overhangs in the tank or areas shaded by Capricornis corals or similar, the Bubble coral can be a good candidate for placing under the overhang.

Bubble corals will occasionally reproduce asexually in the aquarium by budding off a new coral.  This occurs when a piece of tissue starts to grow on the lower edge of the coral.  As the growth gets larger and heavier, it will eventually separate from the parent colony and form a new small colony. 

The bubble coral can also be propagated by using a technique whereby the skeleton is partially cut using a dremel tool or similar and then fractured the skeleton from the bottom side of the coral so that it splits in to two pieces.  This is done carefully so as not to damage the tissue of the coral on the top side.  The coral is then returned to the tank with the 2 pieces of the skeleton held apart using wedges of some type and ideally with an offset to the two pieces of coral when it is put back into the tank.  The goal is to apply a gentle force to the coral tissue that will cause the coral to separate over a period of a couple of weeks thus forming two corals.  Because of the skeletal structure of the bubble coral, it is one of the more difficult corals to propagate this way.

Header photograph by Samuel Chow.  Some other photos courtesy of Nick Hobgood, David Burdick and NOAA which are tagged individually.  Remaining photos by ReefCorner © All Rights Reserved