Ciguatera Poisoning

By Carolyn Shearlock © 2016 • all rights reserved

How much do you really know about ciguatera poisoning? How prevalent is it? How serious is it? What you need to know before you eat another piece of fish.

How do you tell if a fish carries ciguatera poisoning?

Unfortunately, you can’t. Well, not until you’ve eaten it and either gotten sick or not.

And if you get ciguatera, you’re generally not just a little sick . . . you’re really sick, with both gastrointestinal and neurological symptoms. Worse news: there’s no “cure” or antidote. Even worse: symptoms can continue for months to years. More bad news: once you think you’re cured, many things will trigger a new bout – alcohol (even a single beer or glass of wine for some people), nuts, fish (even fish that doesn’t make anyone else sick).

When Gwen recently added a comment about ciguatera and their experience with it to my post about things to know about cruising in the Bahamas, my first thought was that I’ve probably known a dozen people with it. Then Dave and I got talking and it hit me that I knew far more than just a dozen. Maybe 50? 75? Admittedly, some are people I only know through their blogs, but nonetheless I know them. The actual number is probably more as I’m sure that some cruisers I know have had ciguatera and yet I’m not aware of it.

And that led me to wanting to know more, and also to wanting to write about it. I hear of more and more people affected every year, but I’ll be honest that I didn’t realize just how sick most of them were. I’ve also learned that many fish that were considered safe a few years are now on the “caution” list.


Probably half the cruisers I know have “heard of” ciguatera – or that eating reef fish can make you sick. But I think that most are like Dave and I and don’t know much beyond that . . . don’t know how awful the poisoning is (I thought it was a nasty but “typical” food poisoning with gastrointestinal woes that went away after several days) and don’t know what fish can carry it.

It’s not mentioned in most cruising guides and much of the information out there seems to be out of date. Everyone that I know who has gotten ciguatera says that they really didn’t know enough about it before they got it. No one realized that the fish they were eating might carry the disease, or how nasty the disease could be.

So, more than anything, I want to raise awareness.


Ciguatera has long been known to be present in certain reef fish – they eat a certain microalgae toxin and it just goes right on up the food chain, concentrating itself in those top predators such as barracuda and grouper. The ciguatera doesn’t affect the fish, only people (and their dogs and cats, both of which can get deathly ill) who eat those fish.

But now ciguatera is not limited to just top reef predators or even to just reef fish . . . there are over 400 species that are known carriers – and mahi/dorado and tuna are now a listed as carriers (source: Florida Department of Health). It used to be that you only had to avoid the “large” specimens of reef fish; now people are getting sick on smaller fish too. A fish caught on one reef may carry ciguatera while another one caught nearby won’t.

Four things to know:

  • There is no proven test to tell what fish is ciguatoxic and which isn’t. Giving some to ants or a cats and seeing if they will eat it is not reliable.
  • Affected fish (whole or filleted) do not appear or smell any different than those not affected.
  • Cooking or freezing won’t neutralize the poison.
  • In broad average numbers, the chances of getting ciguatera are fairly small. Cruisers seem to have a higher risk, as they tend to eat more fish than average and do in changing locales where they don’t know the local prevelance of ciguatera and what to avoid.

The Florida Public Health Department specifically lists barracuda, grouper, amberjack, snapper, tuna, kingfish, eel, trevally, seabass, mackerel, hogfish, and mahi-mahi as known carriers.

In the reading that I have done, barracuda and grouper – particularly large ones – are the most common ciguatoxic fish. In the Florida Keys, hogfish also have a very high rate of being affected.

It is only recently that I’ve seen mahi/dorado and tuna on the list of carriers (both are pelagic and pelagic fish were always considered “safe”); most older lists don’t include them.

Further, several articles that I’ve read warn of the possibility of mis-labeled fish fillets in fish markets, restaurants and grocery stores. You might not be buying the “safe” fish that you think you are.


Symptoms of ciguatera poisoning can begin as little as 15 minutes after eating a bad fish, but are more likely to first appear 6 to 24 hours later. Gastrointestinal symptoms usually appear first – vomiting, diarrhea and intense stomach pain and cramping – with neurologic symptoms coming one to two days later.

The classic – and unnerving – symptom is that of temperature reversal, with hot items feeling cold and cold things hot (this can be seriously dangerous with people taking scalding hot showers or burning themselves on hot drinks), although not all people get this.

Other neurologic symptoms include extreme itching, numbness and tingling around the mouth, hands and feet, teeth hurting and feeling loose, muscle and joint aches, and painful urination.

Symptoms can last from a few days to years. Older articles tend to talk about the symptoms going away generally within days, making it sound like an annoyance to get but not something that would affect your life for months to years. Newer articles talk about a longer recovery period with the possibility of relapses.


Medical treatment is strongly advised. IVs may be needed to avoid dehydration. There is no cure or antidote, but various drugs can help control the worst of the symptoms. This is something to think about before eating fish in a remote anchorage . . . if you’re seriously ill, you’re going to have a hard time moving the boat to get to medical care.

And the symptoms can recur with the slightest provocation. According to the Florida Health Department, “people reported symptoms recurring months or even years after eating ciguatoxic fish. Triggers may include consuming antihistamines, seafood, chocolate, chicken, nuts, caffeine or alcohol. Participating in strenuous physical activity, taking cold showers, and smoking, may also reactivate symptoms. People affected should avoid unprotected sex and breastfeeding until symptoms subside as, in rare cases, these activities may transmit the toxin to others.”

YIKES! If I get ciguatera, I’m going to have to avoid beer, wine, nuts, chocolate and coffee for a year or more??

One friend described meeting a woman “who had obviously had a severe stroke.” Turned out that no, she had ciguatera two years before and was still recovering. Not everyone gets that severe a case, but some do.


First, be aware of the ciguatera risk. For years, the risk has been considered small and manageable, with the advice being “just don’t eat large reef predators and check with local fishermen to see where the problem areas are.” This is what we had always followed.

Frankly, I think most of us are not aware that the risk is larger and potentially much longer term.

I’m not going to claim there’s a deliberate cover up or anything, but ciguatera is a public health problem that affects numerous industries – fishing, fishing equipment, restaurants, tourism and even charitable fund-raising fish fries. Which of them is going to go out of their way to publicize it?

Recent studies show that more people get ciguatera than cases are reported, but there are no definitive numbers. And they don’t know there has been a real increase in the number of cases or simply “asking the right questions.” Medical and public health experts no longer consider it “rare.”

Second, as the research and knowledge of ciguatera changes over time, stay up to date on the risk wherever you are. For example, when we cruised the Sea of Cortez (2003-08), it was generally accepted that there was no ciguatera there . . . but I have no idea if that’s still true.

I have looked for – and not been able to find – whether ciguatera is riskier for children/elderly/those with other medical problems, but it’s something to consider.

Third, make an informed decision about eating fish. Will you only avoid the top reef predators? All reef fish? Dorado? Tuna? Eat only what the locals are eating (say at a food stall)? Eat fish only when there are nearby medical facilities? Will you eat smaller reef fish? Eat only non-tropical fish?

For many cruisers, catching fish is a way of supplementing the food budget or having fresh food without a refrigerator, not just something fun to do. Dave and I are still discussing this; I don’t have a recommendation for anyone else.


A blogging friend of mine, her family and their guests all came down with ciguatera a few years ago. You can read what happened on It’s a Necessity.

All at Sea magazine has published three articles on ciguatera: read one, two and three

SAIL magazine Voice of Experience

One man’s account of how it progressed for him on Ciguatera Toxin.

An article in SportFishing magazine.

Newspaper article in Freeport News (Grand Bahama island) – Why the Silence?

Public Health Department information.

If you’ve had ciguatera, please leave a note in the comments or put a link to your own story if you blogged about it.

Print Friendly
How to Copy

Do You Find The Boat Galley Useful?

You can support the site when you buy from Amazon by using the links on this site or clicking below. No extra cost to you!



  1. Also known as the ‘seafood diet’? haha – sounds really horrible to have!

  2. Good to know but nothing can be done about it

  3. great article…..we never ate fish the whole 10 years we lived on our boat in the eastern Caribbean. Our Antiguan friends would drink 3 glasses of milk at the first onset of ciguatera. They also told us that any fish without flies on it probably had ciguatera and should be avoided.

  4. Wow, that even the dorado might be listed was surprising to me. We ate quite a few fishes back in 2011-2012 but did avoid barracudas and larger jacks.

  5. Nicola Kamper says:

    We think that Marc suffered from Ciguatera a few months back in the Bahamas. A friend invited us to dinner and served a delicious grouper. Marc got sick but our friend Michael and I did not. Marc was violently ill all night and not quite himself for a couple of days afterwards. I am concerned because apparently the toxin is accumulative. Since we eat the same food, am I just one meal away from tipping the scale and succumbing?

  6. Go straight to the hospital and insist on mannitol treatment

    • A number of newer studies question whether mannitol works or not, and it has a lot of side effects. Something to discuss with whoever is treating you as the recommendations change all the time.

  7. Gwendolyn Webster says:

    Thank you so much, Carolyn, for your thorough writings on this terrible poison. Gary and I are still suffering from these symptoms (is only been one month) and for the most part, learned what to avoid that exacerbates these symptoms. We just got back from Bimini after eating fresh Mahi, Snapper and Grouper. It is extremely annoying and thank goodness that we didn’t need to be hospitalized. High heat outside (the desert, in the shade) and very cool air (A/C blowing directly onto your skin) makes our skin very uncomfortable and feel so odd. The heat reversal and mouth itching along with the tongue feeling like it’s been burned, with cool drinks tasting like bad carbonation leaves us with drinking only room temperature water or tea. Legs and joints still suffer with exhaustion just from walking from one of the boat to the other. Fish was a very large part of our diet. It will be missed.

  8. After reading this, even eating at a local island restaurant could give you this…

    • Absolutely. It’s not just fish you catch yourself. And when I was Googling for info, I found outbreaks such as 17 people getting it at a restaurant in St. Louis — far from the ocean, but fish are air-shipped everywhere now.

  9. I have had it and as I understand it I will be more sensitive to this toxin for ever.
    I did know the dangers of eating reef fish. I landed a huge old Horse Eyed Jack and was fully aware that it could be infected….so(without understanding how the toxin worked) I thought I would take the precaution of just eating a small amount myself before offering it up for dinner to others. I ate a small portion probably about 1/4 lb…I felt fine. The next day I cooked 4 large portions for my husband myself and two friends, at least 1/2 lb but probably more….we were all fine. On the third day I ate the whole rest of the fish all by myself yes, it was gluttony! Probably about another 2lbs…. About 12 hours later,in the middle of the night I woke up so ITCHY all over! Couldn’t sleep. I thought I was having an allergic reaction to the laundry detergent or something. When I began to feel tachycardia, it occurred to me that It could be the fish. We were far far from anywhere at least one day from Turks and Caicos. By the next day I was suffering wit bouts of severe exhaustion, muscle fatigue like I had just run a 6minute mile, just from walking 10 feet. It only lasted a few minutes or so each time but this was the worst part. Cold was hot and hot was cold and the itchiness continued too. The tachycardia went away after about 48 hours but the other symptoms went away very slowly over atleast two months! Sudden onset of fatigue and itchy palms and feet when I least expected it.
    So what I have learned is that the toxin builds up in your system and stays. Some people may get lucky and vomit out much of the toxin before it gets absorbed…. My body didn’t recognize it until it was too late. I will never eat reef fish again but it is clear that I love fish and I refuse to stay away from dorado. This may indeed be foolish, only time will tell

  10. One of the reasons you are seeing fish not previously identified as carriers and more instances among fish that have been known to be are fishing pressure on the affected populations and environmental pressures on oceans. This manifests itself in several ways, plus one wild card.

    As reefs become unhealthy, some reef fish begin eating micro-algaes that are not part of their normal co-evolved food supplies.
    As fishing pressures on stocks increase, more border-line fish (too large) are kept rather than being released, and problematic fish (as you said) are slipped into the human food pipeline.
    As fish populations shrink more apex predators become less selective in their diet.
    As plastic debris rafts increase in number and scale they become the equivalent of unanchored reefs with their own micro-algal flora and open ocean predators become concentrators.
    As humans become more dependent on drugs for health maintenance and food preservatives for supply safety, toxic interactions become more frequent and less manageable.

  11. Gwendolyn Webster says:

    Carolyn: Another note I wanted to mention was that the Poison Control Centers (especially in Florida) want you to keep a piece of the fish that you suspect gave you this toxin. I am sorry that we weren’t able to send the fish we ate to them. They will continue to do testing to try and come up with antidotes and test kits for these fish.

  12. Yes we got it in the Carribean from a mackerel that was given to us from a fellow cruiser. Very itchy palms and feet that came and went for several days.

  13. A Dutch couple just got killed by eating contaminated fish on their honeymoon.

  14. I still think back to how horrible that was!!!!

  15. Serious stuff!!!

  16. I dare you to experiment and develop some boat friendly vegan recipes 🙂

  17. Jeez that is some serious stuff. How is it I’m just now hearing about this? Where are awareness posters for this?!

  18. Was told 25 years ago, be careful what fish you eat. The local St. Thomas fisherman would sell their catch at market, most are reef fish and they will make you sick.

  19. Well, thank you for ruining hog fish for me!

  20. Good info. Question – what about Lion Fish? Don’t they feed on reef fish? We find them very tasty and like the fact that eating them helps reduce the number of this invasive fish.

    • Gwendolyn says:

      The lion fish isn’t on the list of fish to avoid. But I wouldn’t eat any fish that eats from the reef or one that eats the fish who eat from the reefs. You’re right about helping to rid the ocean of these invasive species!

    • I’ve seen articles both ways on lionfish . . . consider its voracious appetite for reef fish, I’d expect it to be on list but it doesn’t seem to be. I’ve read a couple of articles such as this one that talk about the fact that (1) as of 2014, there were no confirmed cases of ciguatera from lionfish and (2) that lionfish toxins and ciguatera toxins are very similar and thus can be confused for one another in standard testing; however, since lionfish toxins break down if the fish is cooked, studies to see if lionfish are ciguatoxic should be done on cooked fish. But I haven’t seen any articles that discuss such a test program being done.

      So at this point all I can say is that I can’t find any reports of anyone getting ciguatera from lionfish. However, ciguatera is quite underreported, so there may be some cases.

  21. Christine Beckstrom says:

    Appreciate the information about ciguatera. My husband and I are retiring next year and will be heading for the Bahamas. I have heard of this toxin but until I read your account did not realize the seriousness of this illness. Along with your information and doing some additional research has helped us with our decision. Although we love seafood, the risk is not worth the possibility of living with the aftermath in our golden years. Great website, we refer to it often.

  22. Merlin Brasil says: appears to indicate progress, including a ‘soon be available’ test kit.

    I’ve now got this solidly on my research ‘radar’ and will follow up as I discover more.


    • Victoria Beaver says:

      What about shark?

    • Merlin Brasil says:

      Found the company making the test kit. Very quick response to my email enquiry:

      “Thanks for your email. We’re currently selling our kit through MARBIONC ( I would be happy to provide you with specific information about the product if you’d let me know what information would be helpful. I’ve also copied in Karin LeMaire with MARBIONC as she would also be able to provide you with additional information as well.

      Sam McCall
      SeaTox Research Inc”

      to which I responded:

      Thanks for the quick response, Sam.

      Frankly, the $500 price tag for the kit pretty much leaves this inquiry dead in the water.

      To elaborate, consider me representing tens of thousands of ocean cruisers, many based in the Caribbean, who fish as part of life on the earth’s oceans. Add to that the many tens of thousands of shore-dwellers who like their seafood!

      The two-hour turnaround time for the test is workable, but nobody in their right mind will spend $500 to test the 5-20 fish they caught, or buy from the store, to avoid the horrible consequences of Cig poisoning. They will simply continue, as they’ve done for generations, playing Russian Roulette with their health.

      What’s needed is a Lab-On-A-Chip specifically targeting the Cig poison. And that would have to be mass producible and relatively cheap. For the populations of villages who depend on fishing for their livelihoods, this could be a critical life-saver.

      Do you know if anyone has run the concentrated Cig poison through a Mass Spec to see atomically what the composition of the nasty agent is?

      Thanks again,

      I’ll let you know as this proceeds.

      • Merlin Brasil says:

        Latest response (and he is definitely speedy and responsive!):

        I appreciate your feedback. We absolutely understand the importance of ciguatera and are working every day to find solutions to the issues presented by ciguatoxin and other marine toxins. Our current product is not designed to be used by laypersons. It is a research product for use in testing laboratories and those administrative labs charged with controlling fisheries. We’re working on future products that would more user friendly as described, but these solutions take time to develop. While a $500 price tag may seem high, it is able to test multiple samples on one plate, depending on format and is priced competitively in the market.

        Again, I appreciate your correspondence and would be happy to provide any additional information about our assay you may find helpful.


        • Merlin Brasil says:

          Following up further, I received this response:

          “Ciguatoxin has been qualified and quantified by mass spec but mass spec presents its own challenges, namely, the cost of equipment that can easily top $500,000 and required knowledgeable users. Facilities that have the equipment and expertise routinely charge $100-200 per sample for analysis. Unfortunately, identification can’t solely lead to a cure. Other methods would be required to cure the actual disease and due to the nature of the ciguatoxin molecule itself, it is very difficult to produce materials that could be used, not only to identify the toxin cheaply, but to treat ciguatera disease. Thus the importance of our test to allow regulatory agencies and researchers to identify high risk fish and make recommendations for public health reasons.”

          • Gwendolyn says:


            Thank you so much for providing this invaluable information! Wow, they are so responsive and interested in the seriousness of this toxin for us boaters – and land folk. This information will go into my getting-larger-everyday-Cig folder.

  23. Ash Willis says:

    Is lobster affected?

  24. Judy McCarten says:

    Good work bringing this information up for discussion. You may also find this enlightening and interesting- good luck and thanks for your notes.

  25. Cookie johnson says:

    So, are fish you catch in the ocean or gulf safe because they are far from reefs? Are shrimp and scallops still safe?

    • It’s long been thought that pelagic (ocean/gulf) fish were okay, but that is getting a little suspect with mahi and tuna now being added to the list of carriers, probably for the reasons ChrisW discussed above. I don’t really know about shrimp and scallops — I’ve found a few people who think they may have gotten ciguatera from both, but nothing very definitive. Also found several cases where the “scallops” turned out to actually be cut from the wings of rays (sold in stores sometimes as “skallops”).

  26. Merlin Brasil says: has some helpful info and possible “cures”.


  27. Dennis Tye says:

    In the Bahamas, i asked a local man about eating barracuda. His answer was “we’ve eaten it all our lives, and are immune to that disease”.
    Just a thought.
    Great article Carolyn, Hi Dave

    • A couple weeks ago, we were at a town barbecue (we were the only out-of-towners; it was definitely NOT a tourist thing) and one of the stalls was selling grilled barracuda with a big sign “Eat at Your Own Risk!” so maybe they’re not ALL immune.

      In all seriousness, as I understand it, the toxin accumulates in people just as in fish. You don’t build up immunity over time, you actually become closer to the tipping point. Locals may seem more immune as they know which areas not to eat fish from.

  28. Just came back from USVI where we caught a huge king mackerel. He provided us with dinner over several nights and ciguatera poisoning forever. None of us had any digestive issues. All neurological (I.e. Itching, hot/cold reversal, headaches, muscle aches, fatigue) Looks like we only had a minor case but are all still symptomatic 4 days past last ingestion.

    • Gwendolyn says:

      Oh, Tiffany, we are so sorry that you contracted this toxin! Gary and I are still symptomatic 6 weeks along. We are better in some ways, so we wanted to let you know that things will look up for you. Most of the fatigue is gone, the muscle aches are less pronounced (we can walk about half a mile before sitting down to rest and stair climbing has gone from an impossible 5 steps before losing breath to now a couple flights of stairs), headaches come on at the oddest times, itching is less but constant and avoiding anything that exacerbates the symptoms has been really helpful. Gary has just started back with drinking a bit of wine even though it makes him itch. I cannot have one sip of alcohol or my skin goes off the charts. A bit of dark chocolate is our choice of dessert after dinner: not for me as it makes my palms and feet itch like crazy. Not eating any fish at the moment is very frustrating as we were huge fish consumers. The cold reversal is the one that still plagues us. We are just now able to drink water that isn’t completely room temperature but still have to use something to protect our hands while holding anything cold from the fridge.

      The Poison Control Center in FL and the FL Health Department has kept tabs on us and now that we are back in CA, the CA Poison Control Center just called to see how we are doing. They have been amazingly helpful and caring and we feel good about helping them will all of our symptoms so that they can keep track of this awful toxin and hopefully, one day very soon, will be able to have a kit to test on fish. We are hoping that you will be well sooner rather than later!

Add Your Thoughts