Crown jellyfish Crown jellyfish Crown jellyfishes are the six families of true jellyfish that belong to the order Coronatae. They are distinguished from other jellyfish by the presence of a deep groove running around the umbrella, giving them the crown shape from which they take their name. Many of the species in the order inhabit deep sea environments. Crown jellyfish are able to make light through bioluminescence. When they are touched, their bells will light up. Otherwise, the bell of a crown jellyfish will look transparent when undisturbed. When they are attacked, crown jellyfish are able to startle, mislead, and distract their
Jellyfish from mild discomfort to extreme pain and death. Most jellyfish stings are not deadly, but stings of some box jellyfish (Irukandji jellyfish), such as the sea wasp, can be deadly. Stings may cause anaphylaxis (a form of shock), which can be fatal. Jellyfish kill 20 to 40 people a year in the Philippines alone. In 2006 the Spanish Red Cross treated 19,000 stung swimmers along the Costa Brava. Vinegar (3–10% aqueous acetic acid) may help with box jellyfish stings, but not the stings of the Portuguese man o' war. Salt water may help if vinegar is unavailable. Rubbing wounds, or