🦀 Depressed Spider Crab (Xenocarcinus depressus)
A Flattened Carapace Colour-Matched to Its Living Host Gorgonian • An Obligate Symbiont, Depending Entirely on One Coral • Extremely Rare, Expert-Only Specialist
 
📋 This species depends entirely on a specific living host, typically a whip coral or gorgonian, for both camouflage and food, and we recommend it only to specialist keepers who already have a suitable, thriving host coral in place before bringing one home. Removed from that exact host relationship, survival isn't realistic.
The Depressed Spider Crab is a tiny decapod crustacean, with a carapace reaching only around 1.5cm, though overall leg span can reach 4.5cm, with a flattened, elongated carapace adapted to closely match the colour and texture of its host gorgonian.
It comes from a wide range across the Indo-West Pacific, including Australia, Indonesia, the Philippines, and Japan, commonly found clinging to the fronds of gorgonian sea fans in the wild. Every Depressed Spider Crab we ship is settled on appropriate host material.
A remarkable adaptation defines this species: it colours itself to closely resemble its specific host coral, offering camouflage from predators while it feeds on captured plankton and mucus from the coral's surface. This is a true specialist relationship, not general decorator-crab behaviour, this species doesn't attach random debris to itself, but instead relies on a colour-matching to its living host.
 
💡 Highlights
🔬 An Obligate Coral Symbiont: Depends entirely on a living host gorgonian or whip coral
🎨 Host-Matching Camouflage: Colours itself to closely resemble its specific coral host
📏 Tiny: Carapace reaches only around 1.5cm, with overall leg span up to 4.5cm
🧠 Expert-Only Species: Requires a suitable, already-established host coral
💎 Extremely Rare: Seldom collected for the trade