Honeycomb Brain Care Guide
Honeycomb Brain (Goniastrea retiformis) is a LPS coral. Care covers 75-175 PAR, medium flow, reef parameters and feeding; beginner level.
Compiled by Aquairi from published sources · Published · Updated
Overview
Honeycomb Brain (Goniastrea retiformis) is a LPS coral in the family Merulinidae. Honeycomb-patterned brain LPS with shallow polygonal corallites. Very hardy and widely distributed.
Taxonomy
- Family: Merulinidae
- Genus: Goniastrea
- Scientific name: Goniastrea retiformis
- Common synonyms: Goniastrea
Habitat
In the wild, Goniastrea retiformis is reported from Indo-Pacific, Red Sea, where it occupies mid to lower reef slopes and lagoons (typically 5-30 m). The species adopts a encrusting 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: 3 months
Placement and lighting
- PAR (placement zone): 75-175 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
Goniastrea retiformis 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 moderately aggressive toward neighbours. Reef-safe with most fish and invertebrates.
Care notes
Difficulty level: beginner. Reported skeletal growth in well-tuned reef tanks is approximately 0.2-0.4 cm/month. Propagation by fragmentation is straightforward for encrusting 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.
Goniastrea retiformis (Honeycomb Brain) Propagation Guide
Overview
Goniastrea retiformis is a brain coral of the family Merulinidae that forms massive colonies, usually spherical or elongate, with a honeycomb arrangement of corallites and well-developed paliform lobes. Its polyps are typically visible only at night. Being a single connected colony, it is propagated by dividing the skeleton.
Reproductive Mode
The colony enlarges through asexual budding of polyps across the honeycomb skeleton, growing one genotype. Reef-building corals of this group also reproduce sexually by releasing gametes for external fertilisation. For aquarium propagation, only the asexual division of the colony is used.
Fragging / Asexual Propagation
- Select a healthy colony and plan a cut between corallite rows.
- Part the massive skeleton with a band saw so each frag keeps whole corallites.
- Rinse skeletal dust and mount each frag cut-side down on a plug or rock.
- Recover in moderate flow under reduced light while the edge tissues over.
Conditions for Propagation
- Stable carbonate chemistry for skeletal regrowth.
- Clean, moderate flow over the cut.
- Reduced light in the first recovery weeks.
- Low nutrients to keep exposed skeleton clear of algae.
Sexual Reproduction
On the reef, brain corals of this family take part in synchronised spawning, broadcasting gametes into the water for external fertilisation, followed by larval settlement. This is not a routine method for home propagation.
Common Challenges
Honeycomb brains are generally hardy, but exposed skeleton after a cut can be colonised by algae or recede if water quality slips. A clean saw cut and stable parameters support a faster heal.