Box jellyfishCubozoa

Box jellyfish possess a bell with a distinct square or box-like shape, which gives the group its common name. This bell is typically translucent or with a subtle, pale coloration and can reach up to 20 cm (8 in) per side. From each of the four lower corners, a short stalk (pedalium) supports one or more long, slender tentacles, capable of extending up to 3 m (10 ft) in some species. A folded rim (velarium) enables powerful jet propulsion, allowing for fast, directional swimming at speeds up to 6 meters (20 ft) per minute.

These jellyfish inhabit shallow coastal waters, including coral reefs, sandy areas, and mangroves, generally from the surface down to 30 m (100 ft). They are active predators, hunting small fish and crustaceans. Box jellyfish possess advanced visual systems, including up to 24 eyes clustered on four sensory structures (rhopalia), which assist in obstacle avoidance and orientation. Encounters for divers are uncommon but possible. Their stings are painful and can leave lasting welts; however, the species responsible for human fatalities in other oceans do not occur in the 🌊 Red Sea.