see textBox jellyfish are best known for the extremely powerful venom possessed by some of their species. The species Chironex fleckeri, Carukia barnesi, and Malo kingi are amongst the most venomous creatures in the world. Stings from such species are excruciatingly painful, either initially or as an after-effect, and are often fatal to their prey and sometimes even for humans. However, not all species of Box Jellyfish are this dangerous to humans.
Box jellyfish venom is the most deadly in the animal kingdom and has caused at least 5,568 recorded deaths since 1954. Each tentacle has about 500,000 cnidocytes which are harpoon shaped needles that inject venom into the victim.[2] Most often, these fatal envenomations are perpetrated by the largest species of box jelly, Chironex fleckeri, owing to its high concentration of nematocysts, though at least two deaths in Australia have been attributed to the thumbnail-sized Carukia barnesi.[3] Those who fall victim to C. barnesi suffer several severe symptoms known as Irukandji syndrome.[4] The box jellyfish actively hunts its prey, rather than drifting as do true jellyfish. It is capable of achieving speeds of up to 4 knots (1.8 m/s).
The venom of cubozoans is very distinct from that of scyphozoans, and is used to catch prey (fish and small invertebrates which includes shrimp and bait fish) and for defense from predators, which include the Butterfish, Batfish, Rabbitfish, crabs (Blue Swimmer Crab) and various species of turtles (Hawksbill turtle, Flatback turtle). Sea turtles, however, are apparently unaffected by the sting and eat box jellies.
