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Marine Animal Encyclopedia

Box Jellyfish Chironex fleckeri

A sting from the box jellyfish can kill a person in only a few minutes, and this small animal is considered one of the most venomous in the ocean. At each corner of its box-shaped, transparent body is a bunch of 15 tentacles. When it is hunting prey such as shrimp and small fish in shallow water, its tentacles extend up to 10 ft (3 m), and swimmers can be stung without ever seeing the jellyfish. In the middle of each flattened side of the box jellyfish is a collection of sense organs, including some remarkably complex eyes. The exact range of this jellyfish in the Indo-Pacific region north of Australia is not known, but other smaller, less dangerous box jellyfish also occur in the Indian and Pacific oceans. Some sea turtles can eat the box jellyfish without being affected by its sting.

The Box Jellyfish's Lethal Venom

The sting of a box jellyfish causes excruciating pain and skin damage and can leave permanent scars. In severe cases, death may occur from heart failure or drowning following loss of consciousness. A box jellyfish antivenin is available in Australia. In northern parts of the country, some beaches are closed to the public for periods between November and April when the jellyfish are most abundant.

Box Jellyfishzoom image
  • Class Cubozoa
  • Diameter Up to 10 in (25 cm)
  • Depth Near surface
  • Habitat Open water
  • Distribution Tropical waters of southwest Pacific and eastern Indian Ocean
Box Jellyfish habitat mapzoom image