Hydnophora rigida Propagation Guide
How to propagate the branching horn coral Hydnophora rigida: cutting branches, healing fragments, and managing its potent chemical aggression in the reef tank.
Overview
Hydnophora rigida is a large-polyp stony coral in the family Merulinidae. Among the genus it is the thin, openly branching form, and aquarists describe it as a fast-growing, hardy species under appropriate conditions. Its branching skeleton makes it one of the more straightforward Hydnophora to divide.
Reproductive Mode
Stony corals of this group reproduce sexually through spawning and asexually through fragmentation and budding. In the aquarium, propagation relies almost entirely on the asexual route: pieces of the colony detached from the parent regrow into independent colonies.
Fragging / Asexual Propagation
Because the colony grows as discrete branches, propagation is done by cutting individual branch tips away from the main structure. A diamond-tipped cutting tool produces a cleaner cut than plier-style nippers, which speeds healing and lowers the chance of infection at the wound. The detached branch is then mounted on a plug or rock.
- Select healthy branches with good polyp extension and full coloration.
- Cut the branch cleanly with a diamond blade or coral saw.
- Mount the frag and allow the cut surface to heal.
- Dip the frag in an iodine-based coral dip to discourage infection.
Conditions for Propagation
Stable reef parameters and medium to medium-high light and flow support recovery of fresh cuts. Clean, low-stress water and steady alkalinity help the wound seal and the branch resume growth.
Common Challenges
The main difficulty is placement rather than survival. Hydnophora is aggressive toward neighbors: it deploys mesenterial filaments carrying digestive enzymes, and aquarists report sweeper tentacles that can extend several inches and damage corals within a few inches of the colony. Frags need their own clear space well away from other corals.