Black stinging "weed" underwater - what is it?

[Christi]

You've gotten great info...and just to confirm from a DM/Instructor's perspective...yes...they can be broken off and floating. A few weeks ago while doing my ascent I felt a sting on my hand. I was in mid-water column, so it wasn't from brushing up against anything. A day or two later, I had a rash on my hand. It takes three to four weeks to completely go away. Applying vinegar as soon as you get back on the boat helps, but since it's too late for that..apply hydrocortizone cream often and be very careful about scratching it...it actually can spread.

 

[FishOutUvH2O]

This was taken last month in Cozumel, a couple of days after my encounter with a Hydroid. . .

There are several "remedies" that people suggested to deal with the itching:
1. Divemaster urine- This just wasn't going to happen!!!
2. Vinegar- I tried this and it helped a little.
3. Hydrocortisone (in Spanish Hidrocortisona) cream, 2.5%- This stuff worked the best. You can get it at pretty much any of the pharmacies down there. Make sure it's the 2.5% one. It's prescription strength, so use it sparingly.

BTW: Don't let Christi (BlueXTSea) see it or she'll scold you for touching the reef!

 

[ggunn]

Or are the symptoms just delayed? That seems to have been my experience with it... it'll take a few moments to realize you had an unfortunate encounter. And I've seen broken bits of it floating around and have done what I can to avoid it. So I guess anything is possible?

Not for me. I got hit on the back of my hand by a hydroid a few years ago and it was like an electric shock the instant I touched it.

 

[Sue Sue]

Thanks Christi for letting us know that it can free float and still do its damage. The second time this happened to me I was actually upset because I didn't think I had come in contact with anything. Also, the one thing that did help a little bit, once I got home was ...of all things, Preparation H. At least the swelling and redness went down somewhat, but it didn't take the itch away. I guess I should have been more aggressive with the Hydrocortisone. Hope I don't have a next time. S

 

[driftin' by]

Not for me. I got hit on the back of my hand by a hydroid a few years ago and it was like an electric shock the instant I touched it.

Interesting... I guess like a bee sting, people react differently. Also, mine never looked as bad as FishOutUvH2O's! Dude, that looks nasty. Ouch! I know one of the times I got it, I was getting in tight to photograph a pesky juvenile spotted drum with my camera and one raked the back of my hand. Other then jerking away thinking I was touching something precious, there was no immediate pain... just a persistent itch that followed with little swelling.

 

[FishOutUvH2O]

. . . Also, mine never looked as bad as FishOutUvH2O's! Dude, that looks nasty. Ouch!

It looked far worse than it felt. I only vaguely remember running into it. It never really itched that bad and has pretty much disappeared. It's scary when you find out what caused it, because those little buggers are everywhere down there. It's kind of funny because random strangers will see it and just say, "Hydroids or jellyfish?" So it's a great conversation piece. Still, I don't recommend touching them if you don't have to.

 

[Christi]

BTW: Don't let Christi (BlueXTSea) see it or she'll scold you for touching the reef!

HEY! Be nice...haha! I didn't scold you that bad

 

[deborahdelamar]

Usually you'll feel it when you are stung by hydroids -- little prickles, not painful. Best to treat the site immediately with vinegar or ammonia to dissolve the bits that are in your skin (jes, Windex is good.) Don't rub! When it starts to itch, soak in the hottest water you can stand for as long as you can stand it. Treat the itchies with whatever works for you: Antihistamine caps or topicals, hydrocortisone cream, or simply seal from the air with hairspray (hairspray works great for itchy bug bites, too.) There's also a cream that's sold at American Pharmacy on Calle 3 near the waterfront that works well for the initial rash -- don't remember the name; starts with an "A." The itching shouldn't last more than a few days. When it stops, treat the rash with anti-scar cream or hydrcortisone cream. The rash takes from about 10 days to a month to dry & heal. It's fine to dive with it but seawater slows healing.

 

[Dave Zimmerly]

I found that lots of hot water did help and a product called "Xyloderm" sold at Cedrual (sp?).

Regards,
Dave (aka "Squirt")

 

[drbill]

It would be interesting to see pix of this species. I dove Belize for several months and didn't have a problem (but I recognized several of the stinging hydroids there). We also get free swimming siphonophores (relatives of the Portuguese man of war) out in Catalina waters that may break up and leave welts if they come in contact with your skin).