Fauna
Species

Bony-eared Assfish

Acanthonus armatus

Also known as Bony-eared Cusk-eel

Dwelling thousands of meters below the surface, this deep-sea cusk-eel drifts through dark abyssal waters propelled by an undulating, tapered tail. Its soft, watery body features prominent opercular spines and one of the smallest brain-to-body weight ratios recorded among teleost fishes. Feeding opportunistically on small pelagic organisms, it conserves energy in the food-scarce bathypelagic realm through neutral buoyancy rather than active swimming.

Deep SeaBathypelagicCarnivorous
Bony-eared Assfish reference
Biodiversity Heritage Library / Public domain · cc0
—observations
—countries
—peak records
Least ConcernConservation statusIUCN Red List categoriesLCNTVUENCREWEXLeast ConcernRed List categories, explained →
Key facts
Diet & preyAmphipods, Copepods, Gelatinous zooplankton
Predators
  • Deep-sea anglerfish
  • Bathypelagic sharks
  • Larger cusk-eels
ThreatsDeep-sea mineral extraction and climate-driven changes in deep currents
HabitatsDeep bathypelagic and abyssal ocean waters
Life span10–20 years
Classification
  1. FamilyOphidiidae
  2. SpeciesAcanthonus armatus
Range & activity
Range data is not available yet.
Safe observation
Interaction riskLow
  1. Low
  2. Moderate
  3. High
  4. Very high
Why interaction risk is low
Safe to observe at a normal distance.
Responsible observation
  • Submersible Observation: Encountered almost exclusively via remotely operated exploration vehicles.
  • Specimen Study: Museum specimens require delicate handling due to their gelatinous body composition.
Related species
Help improve the field guideSomething wrong?

Report a name, category, or profile issue for review.

Checking your Fauna account…