If you step on a spider fish… how to treat the sting?

Here at sea!

Ahh, beach at last! The scorching sun, the scorching sand, the blinding light and the ice-cold water that cannot alleviate these symptoms nor prevent melanoma. You must love this time of year, don’t you?

And as if all this wasn’t enough for our holiday-goer martyrdom, it is not even possible to try to refresh our feet, because there is always the risk of treading on a sharper rock or (God forbid) a spider fish.

What, it has happened already? Well, then sit back, relax, and read the next few paragraphs with great attention. Are you ready? Are you in pain? Oh, I’m sorry, I did not know. Want to get some rest? No, you just want the information? Okay, you don’t have to be rude. I was getting to it anyway… And now I do not feel like continuing.

Right? Okay, okay, let’s go.

1, 2

1, 2, 3. Is this working?

It is?


So let’s review what happened: the spider fish was doing well, hidden and snuggling under the sand to see if he could get a lunch, and you decided to step on it and ruin its rest. How nice of you.

Picada peixe-aranha

Between one and four of its spikes decided to return the friendly gesture by paying a visit inside your skin.

These spikes are sometimes so insistent in their friendliness that they even pierce some shoes, so please thank them properly.

In addition to the initial sting pain, these spikes also have a toxin that, although not lethal, is extremely painful.

Step one: get out of the water, please (by the way, what are you doing reading blogs in the water? Leave the phone for 5 minutes and enjoy life!), and get help. The pain will intensify over the next 30 minutes, and you will enjoy having someone to shout at. If he is a lifeguard, they even pay him to listen to you.

Step two: Get hot water. The hotter the better, but not boiling. Soak the wound in hot water. It feels better, doesn’t it? Now hang in there for at least 15 minutes, but it may take more, so do not rush. The spider fish’s toxin is sensitive to heat, so let it degrade slowly as you imagine in your head the proteins wagging from side to side and breaking up into a deformed, insipid, and a laughable motive for your nerve endings.

When faced with the lack of hot water, people become extremely creative. The important thing is really the temperature, so “beach people” (surfers and fishermen) resort to “walking on the scorching sand”, “the tip of a lit cigar (but not touching!)”, and the one better known as “urinating on the wound”. Since the urine comes at a nice 37°C, this is supposed to be the reason why a lot of people say it works. Adding urine to hot water, on the other hand, lacks evidence.


Ethyl chloride, which usually appears as an analgesic spray, may have some utility, but has the opposite effect of drastically lowering the temperature. This numbs the area but does not help to break down the toxin, so the pain may come back later and spread throughout the body. I do not totally recommend against it, because it may come to have its usefulness, but the first choice and the most effective is hot water. Ether is also present in some life guards’ rescue kits and usually has good results.


Basically, if you have access to a lifeguard, then leave it up to him because they usually know what they have and what usually works best.


Step Three: The most intense pain should be in about an hour or two, and then we may worry about it. Clean the wound, and see if the spike is still there. It is not common for this to happen, but if the spike is still in the wound, it is advisable to have someone experienced to remove it, to make sure that it does not break again and leave small pieces that might infect. After cleaning, the wound should be disinfected (it is not always necessary, it depends on the water and sand of the region), and then it should be left “to air”, which is as it says, do not apply Paw Patrol band aids nor ask the doctor to make a few small dots, nothing. If sand gets in, it can be washed away with water or saline solution. Covering a spider-fish sting tends to increase the risk of infection…

Which brings us to the last issue to address: When should I call the doctor?

Positive side: if you have specialized staff, they know all this and you do not have to remember anything. Second positive part: even if you don’t, this is quite intuitive.

What is normal: pain, itching, swelling in sting area, heat sensation, redness, numbness, tingling. It may also occur: nausea, vomiting, joint pain, headache, abdominal cramps, increased urination, and tremors.

What is not-so-normal-and-maybe-would-be-good-going-to-talk-to-the-doc: arrhythmias, generalized weakness, shortness of breath, sudden low blood pressure, convulsions, gangrene, loss of consciousness. Also be aware of signs of an infected wound: fever, pus, increased pain and swelling.

And this is it, sir. You see? It was not that bad, was it? And now you can take photos and everything to put on your Instagram #SpiderFish. Residual pain usually lasts a few days, sometimes weeks, and there are those who report that months later could still feel pain. But when a month later, at work, they ask you why you’re limping, it’s a great time to show them your Instagram. You see? Always looking for the positive.

Thank you, João!

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