Bubble Coral Care Guide (Plerogyra)
Bubble coral (Plerogyra sinuosa) is one of the most distinctive LPS corals you can own — a cluster of grape-like, water-filled vesicles that inflate under light during the day and deflate at night to reveal feeding tentacles. It’s hardy and beginner-friendly if you respect its two firm rules: low light and gentle flow. Get those right and a bubble coral is a long-lived, showpiece animal. This guide covers lighting, flow, placement, parameters, feeding, aggression, safe handling, and acclimation.
Care Level: Beginner-Friendly (With Two Rules)
Bubble corals are forgiving of water quality but unforgiving of too much flow and too much light. High flow tears the delicate bubbles, and intense light causes them to shrink and stay deflated. Provide a calm, shaded spot and this is an easy coral.
Quick-Reference Care Parameters
| Coral type | LPS (Large Polyp Stony) |
| Care level | Beginner–Intermediate |
| Lighting | Low · PAR 30–100 |
| Flow | Low and gentle |
| Placement | Lower third of the tank |
| Temperature | 76–82°F (ideal ~78°F) |
| Salinity | 1.024–1.026 (~35 ppt) |
| Alkalinity | 8–11 dKH |
| Calcium | 400–450 ppm |
| Magnesium | 1250–1350 ppm |
| Nitrate | 2–10 ppm |
| Phosphate | 0.03–0.10 ppm |
| Feeding | Beneficial · meaty foods ~1× per week at night |
| Aggression | High · long nighttime sweeper tentacles |
Lighting (Keep It Low)
Bubble coral is a low-light animal — think PAR 30–100. Under moderate light the bubbles inflate large and round; under strong light they shrink and the coral looks unhappy. Place it low in the tank or in a shaded pocket, and if you’re moving it brighter, do so slowly.
Water Flow (Keep It Gentle)
Gentle, indirect flow is essential. The vesicles are fragile and tear easily in strong or direct current, and torn tissue invites infection. You want just enough movement to keep detritus from settling — no direct powerhead stream on the coral.
Placement
Put bubble coral in the lower third of the tank, in low light and low flow. Give it generous space from neighbors — see the aggression note below — and a stable footing so it can’t roll.
Water Parameters
As a stony coral, it appreciates stable alkalinity (8–11 dKH), calcium (400–450 ppm), and magnesium (1250–1350 ppm), with steady temperature and salinity. Stability beats chasing numbers. A modest nutrient level (nitrate 2–10 ppm, phosphate 0.03–0.10 ppm) supports good color and tissue.
Feeding
Bubble corals benefit from feeding. At night the bubbles partially deflate and feeder/sweeper tentacles emerge — that’s the time to target-feed small meaty foods like mysis or chopped seafood, about once a week. Feed gently in low flow so the food isn’t blown away, and don’t handle the bubbles while feeding.
Aggression & Spacing
Despite their soft looks, bubble corals extend long, stinging sweeper tentacles at night that can reach several inches and damage neighboring corals. Give them plenty of open space — err on the generous side — and account for those nighttime tentacles, not just the daytime footprint.
Safe Handling
Only handle a bubble coral by its skeleton, never the bubbles. The skeleton edges are sharp and can cut you, and any squeeze or puncture of the vesicles damages the coral. When the bubbles are deflated (e.g., at night or right after purchase) the skeleton is exposed and easiest to grip safely.
Common Problems
- Bubbles shrinking / not inflating: almost always too much light or flow. Move it lower and calmer.
- Torn tissue: from strong flow or rough handling — reduce flow and let it heal in stable, clean water.
- Recession / brown jelly: a sign of stress or infection; improve stability and flow, and treat as you would other LPS (isolate, dip, remove affected tissue).
How to Acclimate Your New Bubble Coral
- Temperature match (15–20 min): Float the sealed bag with lights dimmed to equalize temperature.
- Drip acclimate (30–45 min): Open into a clean container and drip tank water in slowly until the volume roughly doubles.
- Coral dip (5–10 min): Use a reef-safe dip, swirling gently — never blast the bubbles — then rinse in clean saltwater.
- Placement: Set it low, in low light and gentle flow, away from other corals’ reach.
- Let it settle: The bubbles may look small or deflated for a few days after shipping. Leave it undisturbed and they’ll plump back up as it recovers.
Frequently Asked Questions
Why won’t my bubble coral inflate?
The most common causes are too much light or too much flow. Move it to a lower, shadier, calmer spot and give it a few days.
Is bubble coral aggressive?
Yes — it extends long stinging sweeper tentacles at night. Give it several inches of clearance from other corals.
Do bubble corals need to be fed?
They do best with occasional feeding — small meaty foods about once a week when the nighttime tentacles are out.
What is WYSIWYG coral?
WYSIWYG means “What You See Is What You Get” — the exact coral pictured is the one shipped to you.
Shop WYSIWYG Bubble Coral & Care Guides
Browse our live coral for sale for this week’s hand-selected WYSIWYG bubble corals. See more in our library, including the Hammer & Frogspawn Care Guide, the Cynarina Care Guide, and the Goniopora Care Guide.
