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What is this blue bubble with tentacles in Hawaii?

Over the weekend, I had the unpleasant ordeal of being stung by the infamous Portuguese man-o-war (Physalia physalis). Although beautiful, these marine invertebrates are to be avoided at all cost!

What is a “man-o-war”? Are Man o’ War a jellyfish?

Feeling like a jellyfish sting, Man-o-war are NOT jellyfish. The Portuguese man o’ war is a siphonophore which means it’s a colony of the same organism called zooids/polyps, rather than a singular organism like a jellyfish! They are also found at the surface of the water thanks to a gas bubble. The venomous Man-o-war is named after a Portuguese military ship because when the ship opens its masts for sailing, it resembles a fully grown man-o-war (or vice verse).

Is Man-o-war Deadly?

The Portuguese man-o-war packs a vigorous-laser-like sting once coming into contact with bare skin and have been known, although very rare, to cause cardiac arrest leading to death with certain individuals, amongst other complications.
Dead specimens are dangerous even after the air bubble is popped; tentacle pieces can still be active with venom up to a few days. The initial, excruciating pain lasts 1-3 hours, in my experience in about a 1hr, the immediate pain began to lessen after taking care of it.

With a constant looming presence in Hawaiian waters, The University of Hawaii Manoa performed in-depth research on the best way to treat a man-o-war sting.

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A Man o’ War sting can be quite painful and potentially dangerous, as they deliver a potent venom. Here’s what you should do if you or someone else is stung by a Man o’ War:

  1. Rinse with Seawater: If available, rinse the affected area with seawater. Do not use freshwater, as it can actually worsen the pain by causing the nematocysts (stinging cells) to release more venom.
  2. Remove Tentacles: Gently remove any tentacles that are still attached to the skin using a pair of tweezers or the edge of a credit card. It’s important not to touch the tentacles with your bare hands as they can still deliver venom, even if detached.
  3. Vinegar: Some sources recommend applying vinegar to the affected area for about 30 seconds. This might help to neutralize the venom and prevent further release. However, this is a controversial step as vinegar might cause the nematocysts to fire more venom. If you choose to use vinegar, do so with caution.
  4. Hot Water: Immersing the affected area in hot water (104-113°F or 40-45°C) for about 20-45 minutes can help reduce pain and inactivate the venom. Make sure the water isn’t too hot to avoid burns.
  5. Pain Relief: Over-the-counter pain relievers like ibuprofen or acetaminophen can help manage pain and discomfort.
  6. Topical Creams: Some topical creams or gels specifically designed for jellyfish stings might provide relief. Look for those containing lidocaine or similar numbing agents.
  7. Medical Attention: Seek medical attention, especially if the sting covers a large area, if there is an allergic reaction, or if the pain is severe and not subsiding. In some cases, Man o’ War stings can lead to serious allergic reactions or secondary infections.

Remember that everyone’s reaction to stings can vary, and it’s always better to err on the side of caution when dealing with potential allergic reactions or severe symptoms.

It’s also important to note that Man o’ War stings can be dangerous, and in some cases, professional medical treatment might be necessary. If you’re unsure about what to do, or if the person stung is experiencing severe symptoms, it’s best to seek medical attention as soon as possible.


After a Man o’ War sting, there are several things you should avoid to prevent worsening the symptoms and complications:

  1. Freshwater: Avoid using freshwater, as it can cause the nematocysts (stinging cells) to release more venom. Stick to seawater if you need to rinse the affected area.
  2. Rubbing or Scratching: Do not rub, scratch, or vigorously touch the affected area. This can cause the nematocysts to release more venom and potentially lead to further irritation.
  3. Applying Pressure: Avoid applying excessive pressure to the sting area, as this can also trigger the release of more venom.
  4. Using Bare Hands: Do not touch the tentacles or the affected area with your bare hands, as they may still contain venom. Use tweezers or a similar tool if you need to remove tentacles.
  5. Urinating: The myth that urinating on a jellyfish sting helps is not true and can actually worsen the sting. Stick to proper first aid measures like seawater or vinegar, if you choose to use it.
  6. Alcohol or Ammonia: Avoid using alcohol or ammonia on the sting, as they may not be effective and could potentially worsen the situation.
  7. Excessive Heat: While immersing the sting in hot water for a controlled period can help relieve pain, avoid using excessive heat that could burn the skin.
  8. Delaying Medical Attention: If the person stung experiences severe symptoms, allergic reactions, or if the pain and swelling don’t improve with initial first aid, do not delay seeking medical attention.
  9. Ignoring Allergic Reactions: If the person stung is experiencing symptoms beyond localized pain and swelling, such as difficulty breathing, hives, nausea, or dizziness, seek medical help immediately. These could be signs of a severe allergic reaction.
  10. Ignoring Secondary Infections: Keep an eye on the sting area for signs of infection, such as increasing redness, swelling, pain, warmth, or pus. If any of these symptoms develop, seek medical attention.


Lay down and Rest! After a couple of hours or less (typically within 1 hour), the pain will subside. If you prefer, you can do what I’ve been doing: applying coconut lotion. Whenever I’m itchy I rub natural oils or coconut lotion to suppress the urge to scratch!

Luckily, a common myth we grew up with on the Islands is to pee on a jellyfish or man-o-war sting so yes, avoid peeing on the stung area also; it’s just the warmth from the pee that alleviates the pain temporarily.

For a scientific approach to taking care of your wounds, The University of Hawaii professors helped create “STING NO MORE” – a rapid relief for jellyfish and insect stings. Something similar would be this ointment for a jellyfish sting.

Where are they found in Hawaii?

South shores in summer months. However, Jellyfish and man o’ war are constant year-round in Hawaii. Check out this useful Box jellyfish calendar, here.

Unlike man-o-war, the box jelly navigates purposefully toward a light source where the man-o-war is guided by the ocean waves, currents, winds, and tides. However, it’s a good idea to keep track of the moon phases as the man-o-war has been observed to arrive between 6-8 days after the full moon.

In conclusion, if you see one of these Man o’ war on shore, it’s best to avoid them. Let others around you know that they are around because if you see them on the beach, it’s more than probable you will find more than a handful in nearby waters. It is possible to grab the organism by it’s “head” (the bubble area) if you want to move it safely out of a foot-traffic area. The tentacles can be very long and similar to a thin piece of hair that sticks to our human skin like velcro! So again, be wary when around these blue floating bubbles of pain and take immediate precautions.

A-not-so-fun-fact: The Portuguese man o’ war tentacles can reach a length of 160+ feet/ 48 meters.


(personal experience)

I was stung on my right forearm by a Portuguese Man o’ war while surfing on the South Shore of Oahu in May 2019. I felt it immediately but my initial thought was a fishing line got caught on my arm. Split seconds later, I felt searing and intense pain similar to getting burned.


This was my 4th time I remember encountering these unpleasant creatures. After rubbing any remaining tentacles off with the salt water, I figured it wasn’t that bad and I could still surf….big mistake: My arm began throbbing intense pain as I assume the venom was pumping into my veins, where immediately after that my right pec felt tightened as if the muscles were trying to bench press. My chest began to feel like it was getting tighter and a bit more challenging to take full breaths.


Once finally getting onto the shore, I rinsed my board and myself (wound included) with fresh water, from the beach showers, to rinse off any remaining tentacles (try to rinse it all off in the ocean without using fresh water). Through intense pain and heart palpitations, I made it home.


About 30 minutes after getting stung, I put alcohol (avoid) which relieved the pain for me immediately. After making sure it was clean, I jumped into a warm bath where the pain finally subsided to the lowest since being stung. (read above other ways to treat man o war sting)


About an hour and a half after getting stung, the pain settled down and became tolerable. I personally applied coconut lotion from Walmart which helped tremendously and soothed the pain or whenever it became itchy. The entire healing process took 1 week from the day to be fully healed.


DAY 1 – Throbbing pain and came in waves before sleep.
DAY 2 – Scratched once on accident. AVOID SCRATCHING! RESIST!
DAY 3 – Between night 2 and day 3, boil-like-bubbles formed where I didn’t scratch. Also: puss.
DAY 4 – Every time it feels itchy, apply ointment!
DAY 5 – still Occassional waves of itchy ness but scabs begin to form.
DAY 6 – Less and Less itchy, but by this time it’s very manageable – no more boil bubbles.
DAY 7 – Scabs naturally falling off overnight.
DAY 8 – Ocean Therapy is the best remedy out there!


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