MIAMI (CBS4) – Beaches from Miami northward through Broward and Palm Beach County are colorful Friday with yellow and purple flags and blue things in the water.

The flags, set to flutter warnings, are alerting swimmers to be mindful of the pretty blue Portuguese Man-of-War floating in the surf.

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The beauty of the Portuguese Man-of-War is quickly lost when someone comes in contact with one and feels its painful sting, and there have been a lot of those Friday along Florida’s coastline, said Lt. Dawson MacDonald, operations supervisor at the City of Miami Ocean Rescue department.

“I’ve heard on the radio asking for more vinegar and more vinegar, so I know there are a lot of stings out there,” MacDonald said. “That’s how we treat it here.”

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And don’t pick one up, either as they can sting even after washing up on shore.

Reactions to stings vary from person to person, MacDonald said. Some people experience searing pain, others have no reaction, he said.

“Some people like a cold pack, others want hot. We do what is necessary to make it as comfortable as possible,” MacDonald said.

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MacDonald said purple flags should alert swimmers to a problem and advises that beachgoers ask the lifeguard on duty what those dangers are before entering the water. He also said that jellyfish and Man-of-War typically only appear with landward winds, and soon disappear when the breezes turn seaward.