Honeycomb Coral Care Guide
Honeycomb Coral (Diploastrea heliopora) is a LPS coral. Care covers 75-200 PAR, medium flow, reef parameters and feeding; intermediate level.
Compiled by Aquairi from published sources · Published · Updated
Overview
Honeycomb Coral (Diploastrea heliopora) is a LPS coral in the family Diploastreidae. Massive boulder-forming LPS with neat hexagonal corallites. Centuries-old wild colonies recorded.
Taxonomy
- Family: Diploastreidae
- Genus: Diploastrea
- Scientific name: Diploastrea heliopora
- Common synonyms: Diploastrea
Habitat
In the wild, Diploastrea heliopora is reported from Indo-Pacific, where it occupies mid to lower reef slopes and lagoons (typically 5-30 m). The species adopts a massive growth form on hard substrate within zooxanthellate reef communities.
Tank requirements
- Salinity (specific gravity): 1.024-1.026
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Carbonate hardness (dKH): 8-11
- Calcium: 400-450 ppm
- Magnesium: 1280-1350 ppm
- Phosphate (max): 0.03 ppm
- Nitrate (max): 5 ppm
- Minimum system age: 6 months
Placement and lighting
- PAR (placement zone): 75-200 PAR
- Water flow: medium
Mount this LPS coral on the lower or mid rockwork or on the sand bed (for free-living forms) where light is moderate. Strong direct flow can damage the fleshy tissue; aim for indirect, varied movement.
Feeding
Diploastrea heliopora hosts symbiotic zooxanthellae and derives most of its energy through photosynthesis. Additional feeding is generally not required when lighting is adequate.
Compatibility
This coral is passive toward neighbours. Reef-safe with most fish and invertebrates.
Care notes
Difficulty level: intermediate. Reported skeletal growth in well-tuned reef tanks is approximately 0.05-0.15 cm/month. Propagation by fragmentation is straightforward for massive colonies — separate branches or polyps with a bone cutter, glue to plug, allow 1-2 weeks for healing. Maintain stable alkalinity (avoid swings above ±0.5 dKH per day) to preserve tissue health.
Diploastrea heliopora (Honeycomb Coral) Propagation Guide
Overview
Diploastrea heliopora is the sole species in the monotypic family Diploastreidae. It forms massive dome-shaped colonies of great size, reaching a metre or more across, with round, closely packed plocoid corallites about 1 cm in diameter whose walls form a distinctive honeycomb surface. It occurs across the tropical Indo-West Pacific, including the Red Sea, in silty, protected reef environments. The IUCN lists it as Near Threatened, with aquarium collection among the noted threats.
Reproductive Mode
The colony grows by asexual budding of corallites across its honeycomb skeleton, but it does so extremely slowly. Reef-building corals also reproduce sexually by releasing gametes into the water. Any aquarium propagation relies on physically dividing the existing colony.
Fragging / Asexual Propagation
- Only frag a large, healthy colony, and take small pieces so the parent is barely reduced.
- Cut through the dense skeleton with a band saw between corallite rows so each piece keeps intact corallites.
- Rinse off skeletal dust and mount the frag cut-side down on a plug or rock.
- Recover in gentle flow under softened light; expect a long heal before any visible regrowth.
Conditions for Propagation
- Very stable, mature water with steady carbonate chemistry.
- Calm to moderate flow, mirroring its protected, silty natural habitat.
- Reduced light during the extended recovery.
- Low nutrients to prevent algae from colonising bare skeleton during the slow heal.
Sexual Reproduction
In the wild, this reef-building coral reproduces sexually by broadcasting gametes for external fertilisation. Wild colonies can be very large and long-lived. Captive sexual reproduction is not a practical propagation route.
Common Challenges
The defining challenge is speed: this is one of the slowest-healing massive corals, so a cut wound stays exposed for a long time and is at prolonged risk of algae and recession. Fragging is rarely worthwhile and should be reserved for large, thriving colonies.