Finger Leather Coral (Sinularia flexibilis) Care Guide
Sinularia flexibilis is a branching finger leather coral that releases diterpenes suppressing neighbouring corals, so it needs space in the reef.
Compiled by Aquairi from published sources · Published · Updated
Overview
Sinularia flexibilis is a branching, finger-shaped leather coral with flexible lobes extending from a central stalk and eightfold polyp symmetry. Colonies appear yellow, brown, or green depending on the density of their symbiotic algae. WoRMS treats this as a superseded combination, now Sclerophytum flexibile (Quoy & Gaimard, 1833), family Sinulariidae; the knowledge-base name is retained here.
Taxonomy
- Class: Octocorallia
- Family: Alcyoniidae
- Genus: Sinularia
- Scientific name: Sinularia flexibilis
- WoRMS revision: accepted as Sclerophytum flexibile (Quoy & Gaimard, 1833)
Habitat
The species lives in Indo-Pacific tropical shallow waters, including Southeast Asian reefs and the Great Barrier Reef, at depths of 0-30 metres and temperatures of about 20-30 °C. Like all Sinularia it lacks a calcareous exoskeleton, supported by sclerites, and maintains a mutualistic relationship with photosynthetic dinoflagellates that fuel its growth.
Tank requirements
- Temperature: 24-26 °C (75-79 °F)
- pH: 8.1-8.4
- Salinity: 1.024-1.026 SG
- dKH (alkalinity): 8-11
- Calcium: 380-450 ppm
- Magnesium: 1280-1350 ppm
- Nitrate: below 15 ppm
- Phosphate: below 0.1 ppm
- Lighting: ~75-200 PAR (medium)
- Water flow: medium
- Minimum tank age: 3 months
Diet
The coral is photosynthetic, relying on its zooxanthellae for energy, and does not require direct feeding. Maintaining stable alkalinity, calcium, and magnesium supports tissue and sclerite health, while supplemental amino acids may aid growth.
Compatibility
Sinularia flexibilis produces diterpenes, including flexibilide and sinulariolide, that function in chemical defence against predators, microbes, and competing organisms. Through this allelopathy it can suppress nearby corals, so it should be given ample space from other coral colonies. It is otherwise reef-safe with fish and shrimp.
Reproduction
The species reproduces both asexually, through fission and fragmentation, and sexually via synchronized mass spawning that releases gametes for genetic diversity.
Sinularia flexibilis: Fragging and Propagation
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.