Sinularia flexibilis: Fragging and Propagation

Propagating the finger leather Sinularia flexibilis by cutting branch tips and reattaching frags, with notes on its terpene-driven allelopathy and wild spawning.

Overview

Sinularia flexibilis is a finger leather coral of the family Alcyoniidae, forming a branching colony of slender, flexible fingers from a shared base. As a Sinularia its small polyps sit on the surface of the branches, and the colony is reinforced by sclerites while symbiotic zooxanthellae supply most of its energy through photosynthesis.

Reproductive Mode

Aquarium propagation is asexual by fragging the branches, which regenerate into new colonies. The base can also encrust and the colony spreads outward 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

Finger 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 this species should be given space and the slime released during fragging removed from the system.