Fringe Hard Coral Merulina Sp

Fringe Hard Coral (Merulina sp.)

(Also known as Lettuce Coral, Ruffled Coral, or Ridge Coral)

Overview

The Fringe Coral (Merulina sp.) is a visually striking small-polyp stony (SPS) coral, admired for its ruffled, leafy plates and ridged growth pattern that create elegant, wave-like forms. Colonies typically begin as encrusting basesbefore developing upright, frilled, or scroll-shaped plates, giving them a delicate, textured appearance. Colours range from cream and tan to green, purple, or pink, often with glowing edges under actinic lighting. Merulina is relatively hardy for an SPS coral, thriving under strong flow and bright light, making it a beautiful mid-to-upper reef display coral.

Origin

Native to the Coral Sea, Great Barrier Reef, Fiji, Tonga, and throughout the Indo-Pacific region. Found on upper reef slopes and lagoon edges, where it experiences strong, variable flow and bright natural sunlight.

Feeding

The Fringe Coral is photosynthetic, housing zooxanthellae that provide the majority of its energy through photosynthesis. While it does not require direct feeding, occasional supplementation supports growth and colour. Offer weekly feedings of:

• Marine snow or planktonic coral foods
• Phytoplankton and microplankton
• Amino acid and trace element supplements

Lighting

Moderate to high lighting.Merulina thrives under full-spectrum illumination provided by LED, T5, or metal halidesystems.

• PAR range: 150–300 ¬µmol/m¬≤/s
• Gradually acclimate to high light to prevent bleaching.
• Blue-spectrum lighting enhances fluorescence and highlights the coral’s frilled edges.

Water Flow

Moderate to strong, turbulent flow. Consistent water movement is vital to keep detritus from settling between folds and to promote gas exchange. Avoid direct laminar flow, which can stress the tissue along the ridges.

Placement

• Position in the middle to upper regions of the aquarium where both light and flow are strong.
• Secure on flat or sloped rockwork, allowing space for horizontal and upward plate growth.
• Avoid shaded areas, as reduced light can inhibit colouration and slow expansion.

Tank Mates

Reef safe. Compatible with:

• All reef-safe fish (tangs, gobies, wrasses, blennies, etc.)
• Invertebrates such as shrimp, snails, and hermit crabs
• Other SPS and peaceful LPS corals at appropriate spacing

Avoid:

• Aggressive stinging corals (e.g., Galaxea, Euphyllia, Hydnophora)
• Large angelfish or butterflyfish that may nip coral tissue

Aggression

Peaceful.Merulina does not possess long sweeper tentacles and will not harm nearby corals, but its delicate tissue can be damaged by more aggressive species. Maintain 5–10 cm (2–4 inches) of space from neighbours.

Experience Level

Intermediate. While Merulina is more forgiving than some SPS corals, it still requires stable water parameters, strong flow, and consistent lighting. Suitable for aquarists with prior experience maintaining SPS or advanced LPS corals.

Water Parameters

• Temperature: 24–27°C (75–81°F)
• pH: 8.1–8.4
• Salinity: 1.024–1.026 SG
• Hardness (dKH): 8–12
• Calcium: 400–450 ppm
• Magnesium: 1250–1350 ppm
• Nitrate: <5 ppm
• Phosphate: <0.03 ppm
• Tank Size: Minimum 100 gallons (380L) for stability and growth space

Strong nutrient control, consistent alkalinity, and excellent water quality are key to maintaining colour and preventing tissue recession.

Reef Compatibility

Fully reef safe. The Fringe Coral is an eye-catching SPS species that adds unique structure and movement to reef aquariums. Its elegant, frilled plates create a natural reefscape effect and provide a beautiful contrast to branching and encrusting corals. When given space, light, and flow, Merulina becomes a stunning highlight coral for established reef systems.