Care guide · Marine · corals

Candy cane coral

Caulastraea furcata

Species level

Photo: David Siu · Source · CC BY 2.0Resized and compressed; no cropping or colour changes.

Caulastraea furcata, often called candy cane or trumpet coral, forms separate fleshy heads on a branching calcareous skeleton. Its rounded oral discs and colour patterns are visible without exceptionally powerful lighting. It is a relatively approachable LPS for a stable reef, but cannot replace good water management. The accepted scientific spelling is Caulastraea; the frequently used Caulastrea spelling remains available as a search name. Give the colony a firm low position where its heads cannot disappear under sand and gentle water movement removes debris. Supplementary feeding can help if the polyps ingest small particles and tankmates do not constantly pull the food away. Space and intact tissue matter more than rapidly increasing the number of heads.

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At a glance

Identification level: Species level
Coral group: LPS
Difficulty: Easy
Growth and pruning: Moderate
Temperature: 24–26 °C
Specific gravity (SG at 25 °C): 1.025–1.026 SG
pH: 8.1–8.3
Alkalinity: 8–9 °dKH
Calcium: 400–450 mg/L
Magnesium: 1250–1350 mg/L
Light requirement: Low, Moderate
PAR culture preference (not a tolerance limit): 50–70 µmol/m²/s
Flow requirement: Low to moderate
Position: Low, Middle
Aggression: Semi-aggressive
Supplementary feeding: Optional

Water values are reef-care guidance, not proven species limits. PAR describes only the stated culture experience; stability and gradual acclimation remain important.

About this coral

Each head consists of living tissue over a skeletal cup. Retraction makes its boundaries much clearer than when the animal is fully inflated. Stripes and contrasting oral discs occur, but a colour name is not a reliable species diagnosis. Other Caulastraea can appear under similar sales names. Check the basis of identification. This guide follows Caulastraea furcata and its current placement in Merulinidae. Handle a frag by its bare base and avoid pressing the edge of a fleshy head.

Natural habitat

The species is associated with Indo-Pacific reefs. An aquarium frag may instead come from longstanding culture, making its recent lighting and flow conditions relevant when placing it. Branching raises the heads above the substrate. Use that structure in the aquarium: secure the base, keep living parts clean and let water move between branches. A low position is not an instruction to half-bury the heads in sand.

Aquarium and layout

Choose a low rock or suitable holder that a grazing snail cannot overturn. Leave clearance around fully inflated heads and keep the colony beyond the reach of a more aggressive neighbour. Allow for maintenance: debris beside the base should remain removable without injuring the polyps. No universal minimum volume has been responsibly established for this species. A small system is appropriate only when stability, future size and safe separation are actually addressed.

Water conditions

Although candy cane coral is considered relatively forgiving, it can react poorly to abrupt changes. Record salinity, temperature and alkalinity trends. Calcium and alkalinity are consumed in skeletal growth; supplementation is appropriate only when measurements show the need. Magnesium also belongs in the assessment of the entire reef. A contradictory result calls first for checking the test and method. Removing all nutrients or allowing them to accumulate because the coral is called robust are not responsible starting points.

Lighting and acclimation

Low to moderate lighting is a useful direction. One grower describes a narrow preferred zone for its own colonies, but this does not demonstrate hard lower and upper limits for every specimen. The source and this distinction remain recorded internally. Measure where the heads sit and acclimate a new animal gradually to different lighting. A light's position, name or wattage does not tell you how much usable light reaches this low location. Persistent fading or retraction also calls for checking other environmental factors.

Water movement

Gentle indirect flow is more suitable than a continuous jet onto one head. There must nevertheless be enough movement to remove debris. Observe both the polyps and spaces between branches where material can collect. Changing pump direction can work better than increasing flow throughout the aquarium. Temporarily reducing local movement may help with targeted feeding; restore normal circulation afterwards. A poorly circulated pocket should not quietly become stagnant.

Feeding

The species uses light through its symbionts and can also capture small animal-based food particles. Watch when the tentacles respond and offer a modest quantity that is easily ingested. Small pieces of appropriate frozen food are more practical than a large chunk remaining in the mouth for a long time. Do not continue feeding a closed animal. Pay particular attention to fish trying to remove swallowed food from polyps. They can cause injury without being regular coral eaters. Extra feeding requires monitoring waste and nutrients.

Growth and behaviour

A head can develop more than one mouth and eventually separate into distinct heads. The colony thereby becomes wider and denser. This normal process differs from a tear or a rapidly dying edge. Compare photographs to distinguish healthy expansion from daily inflation. Give new heads room and check that the base continues supporting the increasing weight. Promising a fixed number of new heads each month is not useful care advice.

Aggression and spacing

Candy cane coral is generally less overtly aggressive than torch coral, but still has stinging tissue. Do not allow colonies to touch. Watch for tentacles extending farther at other times and for new heads along the outside. A small gap between retracted animals may disappear when they expand. This guide therefore gives no guaranteed safe distance in centimetres. Both neighbours' future size and the direction of water movement belong in space planning.

Keeping with fish

Fleshy heads deserve attention around fish that nip or steal food. A dwarf angelfish with a conditional reef rating does not become safe because this LPS is relatively robust. Observe whether the same head closes whenever a fish passes. Sand-sifting gobies may cover low colonies. Peaceful open-water fish have a different risk profile but still contribute to feeding and waste loads. Use specific relationships when supported and keep unknown combinations visibly uncertain.

Keeping with corals

Duncan coral may fit a similarly gentle zone provided both colonies retain their own space. A torch is an unfavourable immediate neighbour because of its tentacle reach. Fast-growing soft corals and mushroom corals can gradually occupy or shade a low position. Reassess even an apparently peaceful combination as the animals grow. The issue is placement within the same reef, not permission for different species to grow into one another.

Other invertebrates

Marine snails can mainly test how firmly the frag is attached. Shrimp can steal targeted food, and crabs differ greatly in diet and behaviour. Assess exact species and observations; the collective term clean-up crew is no guarantee. Brief closure after a passing snail differs from visible tissue loss. Keep broad groups such as starfish and sea urchins out of automatic safe matches when relevant species information is missing.

Propagation and fragging

The branching form can allow healthy, well-separated skeletal sections to be divided safely. When uncertain, have an experienced grower perform this. Do not force separation through living tissue, or assume a newly divided mouth means the head can immediately be clipped. Protect eyes and hands against mucus and sharp fragments. Attach a frag by dead skeleton or its holder and allow undisturbed recovery. A colony with receding tissue is not a suitable candidate.

Possible problems

For poor expansion, first check pump exposure, damage, sediment and fish approaching the heads. Measurement trends can then help reveal fluctuations. Exposed skeleton, persistently sunken tissue or rapidly spreading slimy deterioration deserves extra attention. Appearance alone is not a certain diagnosis and does not justify an arbitrary treatment throughout the aquarium. Record changes and obtain experienced assessment if loss continues quickly. Minimise disturbance around still-intact heads.

Keeping with other species

Care products

No sufficiently supported match to a specific existing care product has been established for this coral. Follow the feeding and care chapters; an absent product card does not mean feeding or measurements are unnecessary.

Sources & review

This care guide draws on several specialist sources and was last checked on 9 October 2026.

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