Got a photo? Identify fish instantly with the Fishby app.
Open the appDescription
Synaphobranchus kaupii, commonly known as the Cutthroat Eel, is a deep-sea eel belonging to the family Synaphobranchidae. It is characterized by its elongated, snake-like body, distinctive gill openings, and a generally dark coloration adapted for its abyssal habitat. This species is a significant component of deep-sea ecosystems, playing a role as a scavenger and predator.
Physical Characteristics
- Body shape
- eel-like
- Coloration
- Typically dark brown to black, sometimes with a purplish or grayish tinge, allowing for camouflage in the deep-sea environment. The fins are often darker than the body.
- Scale type
- cycloid
- Mouth position
- terminal
- Distinctive features
- Large, crescent-shaped gill openings that extend ventrally, giving the appearance of a 'cut throat'., Absence of pectoral fins in adults (though rudimentary ones may be present in juveniles)., Small, embedded scales that are often difficult to discern., A relatively short snout with a large mouth extending beyond the eye.
- Dorsal fin
- Long, originating well behind the head and confluent with the caudal and anal fins.
- Tail fin
- Confluent with the dorsal and anal fins, forming a continuous fin fold.
- Pectoral fin
- Absent in adults, or greatly reduced and rudimentary in juveniles.
- Distinctive fins
- The continuous dorsal, caudal, and anal fin structure is characteristic of many eels, but the absence of pectoral fins in adults is a key distinguishing feature for Synaphobranchus kaupii.
Identification Tips
Gill Openings
Look for the prominent, crescent-shaped gill openings that extend significantly onto the ventral surface of the head, giving the 'cutthroat' appearance. This is the most reliable distinguishing feature.
Pectoral Fins
Confirm the absence of pectoral fins in adult specimens. If present in juveniles, they will be very small and rudimentary.
Body Coloration
Note the uniform dark brown to black coloration, typical of deep-sea species.
Scales
Observe the presence of small, embedded cycloid scales, which may require close inspection or magnification to see clearly.
Habitat
- Water type
- saltwater
- Depth
- Bathyal to abyssal zones, typically found at depths ranging from 200 meters to over 4,000 meters (650 to 13,000 feet).
- Environment
- Demersal, inhabiting the soft muddy or sandy bottoms of continental slopes, abyssal plains, and oceanic trenches. They are adapted to cold, dark, high-pressure environments.
- Geographic range
- Widespread in the Atlantic, Pacific, and Indian Oceans. Its distribution is circumglobal in deep-sea environments, including the North Atlantic, South Atlantic, Indo-Pacific, and Antarctic waters.
Aquarium Information
- Care level: expert
- Temperament: aggressive
- Diet: carnivore
- Minimum tank size: Not suitable for home aquaria due to specialized deep-sea requirements.
- Temperature: 2-4°C (35-39°F)
- pH level: 7.8-8.2
- Hardness: Not applicable for home aquaria
- Compatibility: Not applicable for home aquaria.
- Special requirements: Requires extreme deep-sea conditions, including high pressure, low temperature, and specific light absence, making it impossible to maintain in a conventional aquarium setting.
Wild Information
- Conservation status: least concern
- Seasonality: No known seasonal patterns; inhabits stable deep-sea environments year-round.
- Market price: None
- Commercial importance: none
- Taste: Unknown, not consumed by humans.
- Texture: Unknown, not consumed by humans.
- Nutritional value: Unknown, not consumed by humans.
Key Facts
Deep-Sea Dwellerinteresting
Synaphobranchus kaupii is a true denizen of the deep, thriving in environments with immense pressure and perpetual darkness.
Unique Gill Structurebehavior
Its common name 'Cutthroat Eel' directly refers to its distinctive, crescent-shaped gill openings that extend far down the throat.
Pectoral Fin Lossamazing
Adult Cutthroat Eels are notable for lacking pectoral fins, a feature that distinguishes them from many other eel species.
Global Distributionamazing
This species has one of the widest distributions among deep-sea fishes, found in all major oceans.
Scavenger and Predatorbehavior
Synaphobranchus kaupii plays an important ecological role as both a scavenger of carrion and a predator of smaller invertebrates and fish in the deep-sea benthos.
Safety Information
Safe- Safety level: safe
- Venomous: No
- Edibility: not recommended
- Handling notes: No specific handling precautions are required beyond standard ichthyological practices for preserving specimens. They are not known to be venomous or possess any harmful spines. Due to their deep-sea habitat, live specimens are rarely encountered by humans.
Similar Species
Shortfin Cutthroat Eel
Synaphobranchus brevidorsalis
S. brevidorsalis typically has a shorter dorsal fin origin relative to the anus and may have slightly different vertebral counts. The gill opening shape can also vary subtly, though both share the 'cutthroat' characteristic.
Longfin Cutthroat Eel
Synaphobranchus affinis
S. affinis generally has a longer dorsal fin origin, starting further forward on the body compared to S. kaupii. Morphometric measurements and vertebral counts are crucial for definitive identification.
Arrowtooth Eel
Dysomma anguillare
While also a deep-sea eel, Dysomma anguillare belongs to a different family (Synaphobranchidae, but different subfamily Dysomminae) and has a more robust body, a shorter snout, and different dentition. Its gill openings are typically smaller and more lateral, not exhibiting the pronounced 'cutthroat' appearance.
Scientific Classification
- Kingdom
- Animalia
- Phylum
- Chordata
- Class
- Actinopterygii
- Order
- Anguilliformes
- Family
- Synaphobranchidae
- Genus
- Synaphobranchus
- Species
- Synaphobranchus kaupii
Explore Cutthroat Eel
Identify fish anywhere
Free on iOS, Android, and Web. Photo identification, full species details, and more.