It has numerous venomous microscopic nematocysts which deliver a painful sting powerful enough to kill fish, and has been known to occasionally kill humans. The Portuguese man o' war is the only species in the genus Physalia, which in turn is the only genus in the family Physaliidae. It is considered to be the same species as the Pacific man o' war, which is found mainly in the Pacific Ocean. The Portuguese man o' war ( Physalia physalis), also known as the man-of-war, bluebottle, or blue bottle jellyfish, is a marine hydrozoan found in the Atlantic Ocean and the Indian Ocean.
