<P> Stings from a Portuguese man o' war are often extremely painful . They result in severe dermatitis characterized by long, thin open wounds that resemble those caused by a whip . These are not caused by any impact or cutting action, but by irritating urticariogenic substances in the tentacles . Treatment for a Portuguese man o' war sting usually begins with the application of poured salt water to rinse away any remaining microscopic nematocysts . Salt water is used as fresh water has been shown to cause nematocystic discharge . </P> <P> Acetic acid or a solution of ammonia and water is believed to deactivate the remaining nematocysts and usually provides some pain relief, though some isolated studies suggest that in some individuals vinegar dousing may increase toxin delivery and worsen symptoms . Vinegar has also been claimed to provoke hemorrhaging when used on the less severe stings of cnidocytes of smaller species . The current recommended treatment from studies in Australia is to avoid the use of vinegar, as local studies have shown this to exacerbate the symptoms . </P> <P> The vinegar or ammonia soak is then often followed by the application of shaving cream to the wound for 30 seconds, followed by shaving the area with a razor and rinsing the razor thoroughly between each stroke . This removes any remaining unfired nematocysts . Heat in the form of hot salt water or hot packs may be applied: heat speeds the breakdown of the toxins already in the skin . Hydrocortisone cream may also be used . </P> <P> The Portuguese man o' war is a carnivore . Using its venomous tentacles, a man o' war traps and paralyzes its prey . It typically feeds on small marine organisms, such as fish and plankton, and has few predators of its own . </P>

Where are the portuguese man of war found