A Xeniid soft coral that forms a low encrusting mat of small, feathery eight-tentacled polyps in a striking powder-blue to teal color, often sold as 'blue clove polyps.' It is hardy and fast-spreading, offering a true blue tone uncommon among soft corals.
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Tiny eight-tentacle polyps ~0.5-1.5 cm on a thin encrusting mat; colonies spread across rock
Lifespan
5–20 years
Social needs
group
Native region
Indo-Pacific reefs, including the Red Sea and western Pacific
Origin
Old World
Climate
🌴 Tropical
Water type
🌊 Marine
Family
Xeniidae
Genus
Sympodium
Part of the Soft Corals
Soft corals such as leathers, colt, cloves, Anthelia, gorgonians and Sympodium. Non-skeletal octocorals with flexible, often swaying colonies and eight-tentacled polyps; mostly hardy, beginner-friendly reef corals driven by photosynthesis and tolerant of a wide range of light, flow and nutrients.
From the minimum an animal needs to be kept humanely, up to the ideal setup. Bigger is almost always better — minimums are floors, not targets.
Photo coming soon
Minimum
Stable nano reef
10+ gal / SG 1.025 / Alk 8-9 dKH / NO3 5-15 ppm
Hardy soft coral — fine in a stable nano reef with low–medium light and gentle flow. Place low/mid; tolerates higher nutrients than SPS. Sympodium (Blue Clove Polyps) — encrusting blue/purple polyps; spreading mat coral.
Photo coming soon
Recommended
Established 30-gal reef
30+ gal / cycled 6+ mo / Alk 8-9 / Ca 420-440
Established 30+ gal reef with stable lighting + mid flow. Photosynthetic; no target feeding required. Frag-friendly — grows fast.
Photo coming soon
Ideal
Mature mixed reef
75+ gal / show-quality stability
Mature 75+ gal mixed reef. Tolerant species like this can compete chemically with neighbours (e.g. xenia, GSP spread fast) — give space or contain on isolated rock. Sympodium (Blue Clove Polyps) — encrusting blue/purple polyps; spreading mat coral.
Life & growth stages
How this animal changes through its life — each stage often has its own care, diet and space needs.
Photo coming soon
Planula larva
Corals begin as a free-swimming planula larva released into the water column after spawning or brooding. The tiny, ciliated larva drifts and swims until it finds suitable hard substrate to settle on.
Photo coming soon
Single polyp
Once settled, the larva metamorphoses into a single founding polyp that secretes a calcium-carbonate (or proteinaceous) base and extends a ring of tentacles to feed. Reef-building corals begin laying down skeleton at this stage.
Photo coming soon
Mature colony
The founding polyp buds asexually into a colony of many genetically identical polyps, building the species' characteristic growth form — branching, plating, encrusting, or massive. A mature colony can reproduce and contributes to reef structure.
Color & pattern variants
Natural variants occur in the wild; selectively bred (man-made) variants were developed in captivity.
Natural
representative
Powder Blue Sympodium
The signature soft powder-blue to teal mat form most commonly traded as 'blue clove polyps.'
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Green-Blue Sympodium
A morph with a greener cast to the polyps and mat, shifting toward teal under blue lighting.
Easy in any stable reef from 40 L (10 gal) up. Keep salinity 1.024-1.026 SG, temperature 24-27 C (75-81 F), pH 8.1-8.4, alkalinity 8-11 dKH, calcium 400-450 ppm, magnesium 1250-1350 ppm. Like other Xeniids it appreciates measurable nutrients and stable trace elements (iodine) and dislikes ultra-sterile systems. Mount it on an isolated rock so its encrusting mat does not creep over neighbors.
Substrate
Encrust onto a dedicated rock, plug, or tile and keep it isolated from the main reef structure, since the mat creeps onto any hard surface it touches. Avoid sand placement. An island rock surrounded by sand is the best containment method.
Equipment & setup
Gentle to moderate flow lets the polyps extend and wave without being flattened while keeping detritus off the mat. Moderate to bright light (~50-150 PAR) intensifies the blue coloration under LED or T5 with strong blue spectrum. Standard skimmer, heater, and an iodine/trace supplement complete the setup; no specialized equipment required.
Diet
Predominantly photosynthetic through zooxanthellae and absorbs dissolved organics directly from the water. Its minute polyps capture negligible particulate food, so target feeding is not needed; maintaining trace elements and a lightly fed tank fuels its spread. Optional fine phytoplankton dosing can support coloration and growth.
Behavior & temperament
Peaceful with no sweeper tentacles or strong sting, but it spreads aggressively by encrusting and can overgrow slower corals. Polyps wave gently in the flow and retract when disturbed; the blue pigment is structural and most vivid under good light. Not handleable beyond fragging; mucus is harmless but gloves are still advisable.
Health
Very hardy, though as a Xeniid it can suffer sudden 'melt-downs' tied to unstable alkalinity, salinity, or low iodine. Polyps that stay closed and a fading blue color indicate a parameter or trace-element problem, or too little/too much light. Keep conditions steady and dose iodine modestly to keep the blue vibrant and prevent crashes.
Tips, DIY & hacks
Place under blue-heavy lighting to maximize the powder-blue color, which can wash out under weak or overly warm light. Frag by cutting a mat-covered chunk and gluing it to a new plug. Keep it on an isolated rock to stop it from encrusting over prized corals. Dose iodine and hold parameters steady to avoid Xeniid-style melts. Do not confuse it with stalked blue Xenia — Sympodium is a flat encrusting mat.
representative
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