Reeflings

Common name: Bobbit Worm

Scientific name: Eunice aphroditois (Pallas, 1788)
Bobbit Worm (Eunice aphroditois)Bobbit Worm (Eunice aphroditois)
Bobbit Worm (Eunice aphroditois)
Bobbit Worm (Eunice aphroditois) almost completely burrowed in the sand, waiting for prey
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General Information

The Bobbit Worm, scientifically known as Eunice aphroditois, is a fascinating and somewhat fearsome marine polychaete worm. Found in warm waters of the Atlantic Ocean and Indo-Pacific regions, this species is known for its ambush predator behavior. Its body length can range from under 10 cm to a staggering 3 meters, making it one of the longest polychaetes. The worm's exoskeleton displays a variety of colors, including black, purple, and iridescent hues, adding to its striking appearance.

The Bobbit Worm is infamous for its sharp mandibles, which it uses to ambush prey. It burrows into soft sediment on the ocean floor, with only its antennae exposed to detect passing prey. When prey is within reach, it strikes with lightning speed, sometimes snapping its victim in half. This predatory behavior has earned it nicknames like "Sand Striker" and "Trap-jaw Worm."

Details

Estimated price
Unknown Rarely available and not recommended for aquariums
Recommended minimum volume
200 liter (53 gallons)
Salinity
S.G. 1.023 to 1.025
Temperature
24 to 28 °C (75 to 82 °F)
Acidity
pH 8 to 8.5
Average size
3 m (10′)
Care level
Very difficult Highly challenging due to its predatory nature and regeneration ability
Pest
Yes Predatory and can deplete aquarium stock
Diet
Omnivore Feeds on fish, algae, and decaying matter in the wild
Reefsafe
No Hunts fish and invertebrates, unsuitable for reef tanks
Aggression
Aggresive Highly territorial and predatory, not suitable for community tanks
Captive bred
No

Taxonomy

  1. Kingdom
    Animals
    Animalia
  2. Phylum
    Segmented Worms
    Annelida
  3. Class
    Bristle Worms
    Polychaeta
  4. Order
    Bristle Worms
    Eunicida
  5. Family
    Bristle Worms
    Eunicidae
  6. Genus
    Bristle Worms
    Eunice
  7. Species
    Bobbit Worm
    Eunice aphroditois (Pallas, 1788)
  8. Synonyms
    Eriphyle aphroditois (Pallas, 1788)
    Eriphyle gigantea (Lamarck, 1818)
    Eunice gigantea (Lamarck, 1818)
    Leodice gigantea Lamarck, 1818
    Leodice gigantea Savigny, 1818
    Nereis aphroditois Pallas, 1788
  9. Source: GBIF | Global Biodiversity Information Facility

Care

While Eunice aphroditois is not a common choice for aquarists, it occasionally makes its way into home aquariums hidden within live rock. However, keeping this species is highly discouraged unless in a specialized setup. Its predatory nature poses a significant threat to other tank inhabitants, as it will hunt fish and invertebrates. Additionally, its ability to regenerate body parts makes removal challenging if it becomes an unwanted guest.

If you do find one in your tank, it is best to remove it carefully to prevent it from splitting into multiple individuals. Specialized traps or professional assistance may be required for successful removal.

Diet and Feeding

In the wild, the Bobbit Worm is a versatile feeder. It is primarily carnivorous, preying on fish and other marine creatures. However, it can also consume algae and decaying organic matter, making it an omnivore. Its diet in captivity would need to replicate this variety, but its predatory habits make it unsuitable for community tanks.

Behavior and Compatibility

Eunice aphroditois is a solitary and highly territorial species. It does not tolerate other individuals of its kind or other species in close proximity. Its aggressive hunting behavior and ability to ambush prey make it a poor choice for mixed-species aquariums.

Interestingly, some fish species have developed mobbing behaviors to deter the Bobbit Worm, showcasing a fascinating predator-prey dynamic in the wild.

Reproduction

The reproductive habits of Eunice aphroditois are not well-documented, but it is believed to reproduce sexually, similar to other polychaetes. Additionally, it can reproduce asexually through fragmentation, where segments of its body regenerate into new individuals. This ability contributes to its resilience and makes it a challenging species to manage in captivity.

Habitat

The Bobbit Worm thrives in sandy and muddy sediments, coral reefs, and areas with abundant prey. It has been recorded at depths of up to 95 meters. Its coloration and slim body allow it to blend into its surroundings, making it an effective ambush predator.