# Box Jellyfish (*Chironex fleckeri*)

> The box jellyfish (Chironex fleckeri) is the most venomous marine animal, with cube-shaped bells and trailing tentacles in northern Australian waters. Adults reach 30 cm bell height and are Least Concern.

- **Category:** Invertebrate
- **Conservation status (IUCN):** Least Concern
- **Range:** Northern Australian coastal waters.
- **Canonical page:** https://globalanimalguide.org/animals/box-jellyfish/
- **Last reviewed:** 2026-07-16

## Scientific classification

- **Kingdom:** Animalia
- **Phylum:** Cnidaria
- **Class:** Cubozoa
- **Order:** Carybdeida
- **Family:** Chirodropidae
- **Genus:** Chironex

## Facts at a glance

| Attribute | Value |
| --- | --- |
| Scientific name | Chironex fleckeri |
| Diet | Carnivore |
| Habitat | Coastal tropical waters |
| Lifespan | 1–2 years |
| Weight | 1–3 kg |
| Top speed | up to 7 km/h |
| Conservation status | Least Concern (IUCN) |

## Cube bell, deadly tentacles

Four-sided bells and up to 15 tentacles each carry millions of nematocysts. Complex eyes on stalks may help navigate mangrove channels toward prey.

## Shrimp and fish in shallows

Fast pulsating swimming lets them hunt in tropical shallows rather than drifting like many jellyfish. Venom can kill fish instantly and humans within minutes.

## Northern Australian coasts

Shallow tropical waters from Western Australia through Queensland. Seasonal stinger nets protect popular beaches in Cairns and Townsville.

## Dangerous but not endangered

IUCN lists Chironex fleckeri Least Concern. Public health measures — vinegar, nets, education — manage risk; populations remain robust.

## Frequently asked questions

### How venomous is Chironex fleckeri?

Its sting can cause cardiac arrest within minutes — among the deadliest venoms known.

### Do box jellyfish have eyes?

Yes — clusters of eyes on the bell may support navigation toward light gaps and prey.

### What should you do for a box jelly sting?

Pour vinegar to disable undischarged stingers and seek emergency medical care immediately.

### When are box jellyfish most common?

Warm wet-season months in northern Australia — stinger nets are seasonal.

### Are box jellyfish endangered?

No — IUCN lists them Least Concern despite their medical danger to humans.

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Source: Global Animal Guide (https://globalanimalguide.org/animals/box-jellyfish/). Licensed CC BY-NC 4.0 — free for non-commercial reuse with attribution.