Bubble Coral: Vesicles by Day, Sweepers by Night

Bubble coral is the easiest identification in the LPS section: by day, Plerogyra inflates a mass of grape-like vesicles until the skeleton disappears entirely. The bubbles are not tissue growth — they are water, expanded to catch light — and they deflate every evening so the feeding tentacles can come out. A coral that looks completely different at night than at noon is normal here, not a warning sign.

The vesicles are also the care instruction. They are thin-walled and tear on sharp rock or in blasting flow, and a torn vesicle is the most common way a healthy bubble coral gets in trouble. Give it a stable perch it cannot fall from, gentle indirect flow, and nothing abrasive within touching distance.

Care at a glance

Space it like a torch: the sweepers reach farther than the daytime bubbles suggest, so measure the exclusion zone from the expanded coral, not the skeleton. Fleshy LPS handling rules apply — the same never-out-of-water-by-the-flesh care described for open brains. Browse the rest of the species directory for tank mates that stay out of range.

The bubbles go down at night. That is normal.

A bubble coral inflates its vesicles during the day to catch light and deflates them at night, when it puts out feeder tentacles instead. People buy one, look at the tank after dark, see a shrunken thing on a skeleton and think it is dying.

Judge it in the middle of the day. A healthy bubble is turgid and smooth, with the vesicles standing away from each other. What you actually watch for is a colony that will not inflate at midday, or one where bubbles have gone slack and papery on one side while the rest is fine.

The reach is much longer than the coral

Bubble corals have some of the longest sweeper tentacles of anything commonly kept. Those tentacles come out at night, extend well past the visible edge of the bubbles, and will burn a neighbor that looked comfortably clear at noon.

Give it a bare patch. Nothing downstream, nothing on the same ledge, and remember that the bubbles themselves expand a long way past the skeleton, so the footprint you have to plan around is the inflated one plus the sweepers on top of it.

Do not touch the bubbles, and keep the flow low

The vesicle wall is thin and it tears. A finger, a pair of tongs, a piece of rock knocked loose in a rescape, or a powerhead pointed at it will all do damage that the coral then has to close over. Handle it by the skeleton only.

Flow should be gentle and indirect. Strong direct flow keeps the vesicles from inflating at all, and a bubble coral that cannot inflate cannot feed itself with light. Low to moderate lighting on the lower half of the tank suits them, which conveniently is also where the flow is usually softest. Ours are photographed in our Key West systems, and on a WYSIWYG listing the photo is the exact animal that ships.

Bubble corals in stock now

One thing to know before you order: the $10 Box & Handling Fee is charged by the box, not by the coral, and UPS Next Day Air is one flat shipping charge per order. A box holds several corals for the same $10 Box & Handling Fee and the same overnight ride, Florida orders under 6 lb ship UPS Next Day Air for a flat $30, and livestock orders of $349 or more ship free. If this page puts one coral on your list, it is worth seeing what else belongs in the box — start with corals under $100 or the newest WYSIWYG pieces.

Our stony corals are either aquacultured at the shop in Key West under Florida Aquaculture Certificate #AQ0254072 or conditioned in our Key West systems before they ship, and the photo on a WYSIWYG listing is the exact animal that ships. Corals ship UPS Next Day Air every Tuesday and Wednesday. If you are ever in Key West, come see the raceways.