Box Jellyfish (Chironex fleckeri)

Common Name

Box jellyfish, sea wasp


Chironex fleckeri

Size and Appearance

A large but almost transparent jellyfish with a box-shaped bell up to 38cm in diameter. Up to 17 ribbon-like tentacles arise from each of the four corners. These may contract to about 10cm or may extend up to 3m.


Size relative to human


Shallow, tropical Australian waters north of Agnes Water, Queensland, all Northern Territory waters and Western Australia south to Exmouth. Stings from Chironex have been recorded predominantly in coastal areas.


Distribution in Australian waters

First Aid

Its sting causes immediate severe burning pain and whip-like marks, often with tentacles remaining on the stung area. Severe stings may cause the casualty to stop breathing and suffer cardiac arrest.

  1. Remove casualty from water if safe to do so
  3. If casualty has more than one localised single sting or looks/feels unwell, dial triple zero (000) and seek assistance from a lifeguard if available
  4. Assess casualty and commence CPR immediately if required
  5. If possible, treat the sting by pouring vinegar for at least 30 seconds and then pick off the tentacles
  6. If vinegar is not available, pick off tentacles (this is not harmful to the rescuer) and rinse well with sea water. Apply a cold pack or ice in a bag for analgesia

Severe Chironex sting

Did You Know?


Box Jellyfish Factsheet

Factsheet Booklet