Grandis Branching Hydnophora Care Guide
Grandis Branching Hydnophora (Hydnophora grandis) is a LPS coral. Care covers 100-200 PAR, medium-high flow, reef parameters and feeding; intermediate level.
Compiled by Aquairi from published sources · Published · Updated
Overview
Grandis Branching Hydnophora (Hydnophora grandis) is a LPS coral in the family Merulinidae. Larger-polyp branching Hydnophora from Australia. Brilliant green when properly lit; aggressive to neighbors.
Taxonomy
- Family: Merulinidae
- Genus: Hydnophora
- Scientific name: Hydnophora grandis
- Common synonyms: Aussie Branching Hydno
Habitat
In the wild, Hydnophora grandis is reported from Australia, where it occupies mid to lower reef slopes and lagoons (typically 5-30 m). The species adopts a branching 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): 100-200 PAR
- Water flow: medium-high
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
Hydnophora grandis 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 very-aggressive toward neighbours. It extends sweeper tentacles capable of stinging adjacent corals, so leave generous spacing (10-20 cm) between colonies. Reef-safe with most fish and invertebrates.
Care notes
Difficulty level: intermediate. Reported skeletal growth in well-tuned reef tanks is approximately 0.3-0.7 cm/month. Propagation by fragmentation is straightforward for branching 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.
Hydnophora grandis Propagation Guide
Overview
Hydnophora grandis is a branching large-polyp stony coral of the family Merulinidae, recognized for noticeably larger polyps than the thinner-branched H. rigida. Like its relatives it grows as discrete branches, which is the trait that allows it to be propagated by simple division.
Reproductive Mode
The genus reproduces sexually by spawning in the wild and asexually through budding and fragmentation. Aquarium propagation depends on the asexual pathway, where a severed branch heals over and continues growing as a clone of the parent colony.
Fragging / Asexual Propagation
Propagation is done by cutting a branch from the colony. A clean cut from a diamond blade or coral saw heals faster and is less prone to infection than a crushed cut from blunt nippers. The branch is mounted and given time to seal at the wound before being placed in its permanent spot.
- Choose a vigorous branch away from the colony base.
- Make a single clean cut with a diamond blade or saw.
- Affix the frag to a plug or rock and let the cut heal.
- Apply an iodine-based dip to protect the fresh wound.
Conditions for Propagation
Recovery is best in stable water with medium to medium-high lighting and flow. Consistent alkalinity and clean conditions help the cut surface close and the branch re-establish polyps.
Common Challenges
As with the rest of the genus, the principal risk is aggression toward tankmates. Hydnophora extrudes mesenterial filaments loaded with digestive enzymes and can produce sweeper tentacles reaching several inches, killing back corals placed too close. A new grandis frag should be isolated with a generous buffer of open rock.