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.

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 WoRMS treats this as a superseded combination, now Sclerophytum flexibile (Quoy & Gaimard, 1833), family Sinulariidae; the knowledge-base name is retained here.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.