Sinularia polydactyla: Fragging and Propagation

Propagating the highly branched finger leather Sinularia polydactyla by cutting branch tips and reattaching frags, with notes on its terpene allelopathy and wild spawning.

Overview

Sinularia polydactyla is a highly branched finger leather coral of the family Alcyoniidae that can spread quickly under good conditions. As a Sinularia it carries small polyps on the surface of its branches, the colony is reinforced by sclerites, and it relies mainly on symbiotic zooxanthellae for energy.

Reproductive Mode

Home propagation is asexual by fragging the many branches, which regenerate into new colonies; the base can encrust and the colony spreads over rock. Sexual broadcast spawning occurs in the wild but is not a practical home method.

Fragging / Asexual Propagation

Cut one or more branch tips with a clean, sharp blade. Because the slick tissue does not hold glue well, frags are banded, held in mesh or an onion bag, or rested on rubble in low flow until they attach; once anchored they may be glued. An iodine dip followed by a seawater rinse after cutting cleans the wound and clears slime.

Conditions for Propagation

• Lighting: 75-200 PAR (medium)
• Flow: moderate, increased after attachment
• Temperature: 24-26 C
• Mature tank: at least about 3 months old
• Give space from other corals due to allelopathy

Sexual Reproduction

Gonochoric octocoral colonies broadcast eggs or sperm; fertilised eggs become planula larvae that drift, settle and bud into colonies. This route is natural but is not used to multiply the species at home.

Common Challenges

Branching leathers periodically close and form a shiny waxy film that is shed within a few days before the polyps reopen. Sinularia is notably toxic among soft corals, exuding terpene-based allelopathic compounds that can inhibit nearby corals, so a fast-spreading species like this should be given room and the slime released during fragging removed from the system.