Description
Sun Hard Coral (Tubastraea sp.)
(Also known as Sun Coral, Sunburst Coral, or Orange Cup Coral)
Overview
The Sun Hard Coral (Tubastraea sp.) is a brilliantly coloured large-polyp stony (LPS) coral, renowned for its radiant yellow-orange polyps and sunburst appearance. Each tubular polyp opens into a delicate, flower-like structure, creating a vibrant display reminiscent of a blooming bouquet. Unlike most corals, Tubastraea is non-photosynthetic, meaning it does not rely on light for energy and must be manually fed. Though it requires more attention, its spectacular colour and movement make it a prized showpiece for experienced reef keepers. When well-fed, it opens fully both day and night, adding life and texture to shaded areas of the aquarium.
Origin
Native to the Indo-Pacific region, including the Coral Sea, Great Barrier Reef, Fiji, Tonga, Indonesia, and the Red Sea. Found in shaded reef caves, overhangs, and crevices, where light levels are low but planktonic food sources are abundant.
Feeding
The Sun Coral is non-photosynthetic and relies entirely on manual feeding for survival. It must be fed at least 3–4 times per week, though daily feeding yields the best polyp health and growth. Feed with:
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Mysis shrimp or enriched brine shrimp
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Finely chopped seafood (clam, shrimp, fish)
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Marine plankton, rotifers, or coral blends
Feed when polyps are open — typically in the evening or after target feeding cues (such as introducing a small amount of food to the water). Each polyp should receive food directly via a pipette or turkey baster.
Lighting
Low lighting. Tubastraea does not require light for photosynthesis.
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PAR range: <50 µmol/m²/s
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Ideal for shaded or overhung areas of the aquarium.
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Excessive light may promote nuisance algae growth around the coral’s base, so positioning in dim areas is preferred.
Water Flow
Moderate, indirect flow. Provide enough water movement to carry food particles and prevent detritus buildup, but avoid strong, direct currents that may prevent polyps from opening fully.
Placement
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Place in shaded or low-light areas of the aquarium such as under rock overhangs, in caves, or vertical reef faces.
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Can be attached to rockwork, overhangs, or placed on the substrate.
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Ensure easy access for regular target feeding.
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Allow 10 cm (4 inches) spacing from other corals to avoid irritation or stinging.
Tank Mates
Reef safe with caution. Compatible with:
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Peaceful reef fish (gobies, wrasses, clownfish, blennies, etc.)
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Invertebrates such as shrimp, snails, and hermit crabs
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Other LPS or soft corals with adequate spacing
Avoid:
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Aggressive corals that may extend sweeper tentacles into the Tubastraea colony
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Fish known to pick at polyps (e.g., butterflyfish, some angelfish)
Aggression
Moderate. Tubastraea may extend short tentacles capable of mild stings to defend its space, but it is primarily passive. Ensure sufficient spacing from neighbouring corals.
Experience Level
Advanced. The Sun Coral’s non-photosynthetic nature makes it demanding — requiring regular, dedicated feeding and stable water parameters. Suitable for experienced aquarists ready to maintain a coral that rewards care with stunning, daily displays of colour and movement.
Water Parameters
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Temperature: 24–27°C (75–81°F)
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pH: 8.1–8.4
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Salinity: 1.024–1.026 SG
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Alkalinity (dKH): 8–12
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Calcium: 400–450 ppm
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Magnesium: 1250–1350 ppm
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Nitrate: <10 ppm
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Phosphate: <0.03 ppm
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Tank Size: Minimum 100 litres (25 gallons); larger tanks provide better nutrient stability
Stable, clean water and consistent feeding are key to long-term success with this coral.
Reef Compatibility
Reef safe. The Sun Hard Coral is a spectacular, motion-filled coral ideal for shaded reef areas where photosynthetic species won’t thrive. When properly cared for, it will reward aquarists with regular polyp extension and vibrant colouration that stands out in any lighting setup.