Invertebrate atlas

Geographical Origin and Habitat: The Duncan Coral (*Duncanopsammia axifuga*) is an iconic, exceptionally beloved Large Polyp Stony (LPS) coral natively endemic to the warm, sandy, and deeper reef regions of Australia, specifically heavily populating the western and northern coasts. Their natural biotope is defined by slightly deeper, lower-light environments characterized by soft, sandy or muddy bottoms where their calcified, branching skeletal structures are frequently anchored directly into the soft substrate.

Taxonomy: Scientifically classified within the Dendrophylliidae family, they are the solitary surviving species within their genus. Morphologically, they are an LPS coral possessing a heavy, tubular, calcified branching skeleton. Extending from the top of each skeletal tube is a mesmerizing, highly fleshy, disc-like polyp surrounded by a dense ring of relatively short, thick, slightly tapering tentacles. A healthy, fully extended colony looks like a beautiful bouquet of underwater daisies.

Social Behavior: They are sessile and universally recognized as one of the most docile, peaceful, and non-aggressive stony corals available. They completely lack the long, potent sweeper tentacles utilized by aggressive LPS corals like *Euphyllia* or *Galaxea*. They pose absolutely zero stinging threat to any neighboring corals, making them an ideal, worry-free addition to tightly packed, community reef aquariums. They spend their day fully extended, swaying gently in the current.

Coloration and Sexual Dimorphism: Sexual dimorphism is non-existent. Their coloration is iconic and highly consistent, though subtle variations exist. The dense ring of fleshy tentacles is typically a pale, ghostly green, mint green, or light pinkish-beige. The central oral disc is usually highly contrasting, presenting in a vibrant, glowing neon green, deep teal, or occasionally purplish hue. Under actinic blue LED lighting, the entire coral (especially the central disc) emits a strong, neon-green fluorescence.

Tank Setup: The aquarium architecture must accommodate their moderate lighting needs and rapid branching growth. A minimum 75-liter (20-gallon) marine aquarium is perfectly suitable.

CRITICAL REQUIREMENT: They should be securely epoxied to the rockwork in the lower-to-middle sections of the tank, or even placed directly on the sand bed (mimicking their natural habitat). They strictly require low to moderate, chaotic water flow to prevent tearing their fleshy polyps against the skeleton.

Diet and Feeding: While they possess symbiotic zooxanthellae and are autotrophic, they are, by nature, ravenous and highly capable carnivores.

CRITICAL FEEDING STRATEGY: The Duncan Coral is famous for its massive appetite. Target feeding them 2-3 times a week with thawed Mysis shrimp, Brine shrimp, or specialized LPS pellets is highly entertaining and aggressively recommended. Actively fed Duncan colonies will exhibit explosively fast skeletal growth, rapidly sprouting new heads from the base.

Water Quality: They are exceptionally hardy, incredibly forgiving of minor mistakes, and widely recommended as a "beginner" LPS coral. They demand stable tropical heat (24-27°C / 75-81°F) and salinity between 1.024 and 1.026. Because they synthesize a heavy branching skeleton, they require pristine, stable levels of Calcium (420-450 ppm), Alkalinity (8-10 dKH), and Magnesium. They actively prefer slightly nutrient-rich water and will thrive with low-to-moderate Nitrate (5-15 ppm) levels.

Compatibility and Tankmates: Compatibility is universally absolute regarding peaceful tankmates. They are 100% reef-safe and completely harmless. Because they do not deploy sweeper tentacles, they can be placed relatively close to other peaceful corals.

CRITICAL WARNING: Their absolute lack of defense makes them highly vulnerable. They MUST be kept well away from aggressive *Euphyllia* corals, which will easily sting and kill them. They frequently serve as a safe, surrogate host for Clownfish.

Aquarium Breeding: Propagating (fragging) the Duncan Coral is straightforward, low-risk, and highly common. As the colony matures, it will rapidly sprout new, miniature heads (polyps) from the calcified base of the main stalks. Once these new branches have grown sufficiently long and calcified, aquarists can simply use bone shears or a Dremel tool to cleanly cut the skeletal branch below the living tissue. The frag is glued to a plug and will quickly heal.

Risks and Diseases: The primary risk to the Duncan Coral is physical damage from excessive water flow; high-velocity laminar flow will blast the flesh against the skeleton, leading to deep lacerations, retraction, and eventual death. The second risk is starvation; while they can survive on light alone, they truly require supplemental feeding to thrive. The third risk is chemical warfare; their peaceful nature leaves them defenseless against the toxic stings of neighboring aggressive corals.