Overview
The Coffinfish (Chaunax endeavouri) is a delightfully bizarre and charismatic deep-sea anglerfish native to the bathyal continental slopes off southeastern Australia and the Tasman Sea. Resembling a spiny, bright-pink water balloon equipped with arm-like fins, this benthic creature belongs to the goosefish and frogfish lineage (Lophiiformes). Resting silently on the deep oceanic silt at depths down to 2,400 feet (730 m), the coffinfish is renowned for its remarkable ability to inflate its body with seawater and ‘hold its breath’ beneath the crushing hydrostatic pressure of the abyss.
Biology and Physical Characteristics
The anatomy of Chaunax endeavouri is an engineering wonder of deep-sea buoyancy and benthic movement. Its body is sub-globular and coated in loose, velvety skin densely studded with microscopic spiny denticles that give it a suede-like texture. Dorsally, it exhibits vibrant shades of rosy pink, reddish-orange, and pale cream, providing countershading against downwelling blue light in deep mesopelagic depths. On its snout sits a modified first dorsal spine transformed into an angling rod (illicium) terminating in a mop-like tassel of sensory filaments (esca), which it can retract into a concave depression between its eyes. Remarkably, its pelvic and pectoral fins are heavily muscularized, functioning like stubby legs that allow the fish to walk across ocean sediments.
Behavior and Ecology
Coffinfish are solitary, stationary ambush predators that spend days perched motionlessly on soft muddy seabeds. To lure quarry in the pitch-black gloom, the fish lowers and twitches its sensory esca above its mouth, mimicking a wriggling invertebrate. When an unsuspecting deep-sea shrimp or small teleost fish inspects the lure, the coffinfish drops its cavernous lower jaw in milliseconds, engulfing the prey with an immense vacuum intake. Groundbreaking scientific ROV observations demonstrated that when threatened, the coffinfish swallows massive quantities of water into its gills, swelling its body volume by over 30 percent and halting gill ventilation for up to four minutes to deter predators.
Conservation and Human Impact
The IUCN classifies Chaunax endeavouri as Least Concern due to its relatively wide bathyal distribution and lack of targeted commercial exploitation. While deep-water commercial bottom trawling for orange roughy and blue grenadier occasionally catches coffinfish as discarded bycatch, their rocky canyon refugia and steep slope habitats insulate large portions of the population. Ongoing oceanographic surveys by Australia’s CSIRO continue to document their population health and deep-sea benthic community associations.
Interesting Factoid
The coffinfish can inflate its body with water like a spiny balloon and hold its breath underwater for up to four minutes at a time without pumping its gills, saving vital energy on the oxygen-starved ocean floor.
Last updated: October 2026