Guides
Ciguatera in Puerto Rico: reef fish poisoning and what to do
Ciguatera in Puerto Rico is a real risk: it is poisoning from reef fish, such as barracuda, grouper or snapper, that carry natural toxins. It starts with vomiting, diarrhea and belly pain hours after the meal, then tingling and a feeling that cold things burn. There is no antidote; treatment eases the symptoms. If you have trouble breathing, feel faint or have a slow pulse, go to the ER.
Is it an emergency? Call 911.
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Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Trouble breathing
- A very slow or irregular pulse, or chest pain
- Severe dizziness or fainting (low blood pressure)
- Vomiting or diarrhea that stops you keeping fluids down, or signs of dehydration
- Worsening weakness or confusion
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What is ciguatera?
Ciguatera is poisoning from eating fish that have built up ciguatoxins, toxins made by marine algae that move up the reef food chain. The fish looks, smells and tastes normal.
According to the CDC, ciguatera occurs in tropical and subtropical waters and is common in the Caribbean. The FDA reports that unsafe ciguatoxin levels have been found in fish from specific areas of Puerto Rico and the U.S. Virgin Islands.
It is not the same as food poisoning from bacteria or a stomach virus: if you ate something and have vomiting and diarrhea without nerve symptoms, see stomach bug in adults.
Which fish can cause ciguatera
The risk is highest with large, long-lived carnivorous reef fish. According to the FDA and CDC, it has been linked to:
- Barracuda
- Grouper and sea bass
- Snapper
- Jacks and amberjack
- Moray eel
- Mackerel, parrotfish, wrasse and tang
Ciguatera symptoms
According to the CDC, stomach symptoms usually start 3 to 6 hours after eating the fish, though they can take up to 30 hours. Nerve symptoms follow, and they are what set ciguatera apart: according to the CDC table, they can start up to 96 hours (4 days) after the meal.
- Nausea, vomiting, diarrhea and belly pain
- Tingling or numbness in the lips, hands and feet
- Temperature reversal: cold things feel hot and hot things feel cold
- Pain or burning when touching cold water
- Pain in the teeth, muscles or joints
- Itching, weakness and dizziness
- A slow pulse, irregular heartbeat or low blood pressure (in more serious cases)
When to go to the ER
Ciguatera can affect the heart and blood pressure: according to the CDC, it can cause a slow pulse, heart block or low blood pressure. These signs need heart monitoring and IV fluids in an emergency room. Don’t book a video visit: go to the emergency room or call 911 if after eating fish you have:
- Trouble breathing
- A very slow or irregular pulse, or chest pain
- Severe dizziness or fainting (low blood pressure)
- Vomiting or diarrhea that stops you keeping fluids down, or signs of dehydration
- Worsening weakness or confusion
Treatment: there is no antidote
The CDC explains that there is no specific antidote: treatment is supportive and targets each symptom (fluids, and medicines for nausea, itching or pain). In the hospital, IV mannitol is sometimes used, mainly within the first 48 hours; the evidence for it comes from uncontrolled studies.
There is also no lab test to confirm it in people: the diagnosis is made from the symptoms and a recent meal of reef fish.
Nerve symptoms usually last days to weeks but can persist for months or even years. To avoid making them worse, the CDC advises avoiding alcohol, caffeine, fish and nuts for 6 months or more after you recover, because they can bring symptoms back.
What to do if you think you have ciguatera
If you get vomiting, diarrhea or tingling in the hours or days after eating reef fish:
- If you have any of the emergency signs above, call 911 or go to an emergency room.
- If not, take small, frequent sips of fluid so you don’t get dehydrated.
- Tell the people who ate the same fish: they may get symptoms too.
- Avoid alcohol and caffeine, and don’t eat fish or nuts while you recover.
- See the doctor by video to review your symptoms and what to watch for.
How we help by video
If you have no emergency signs, you can see Dr. Diana Nieves Castro by video, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. The doctor asks which fish you ate and when, checks how you are keeping fluids down and what signs to watch for.
If appropriate, the doctor prescribes for nausea, itching or pain and we send your prescription to your pharmacy. If nerve symptoms last for weeks, a follow-up visit helps you keep track. See how to prevent dehydration.
Doctor online 24/7: video visits around the clock, so if symptoms start at night after dinner, request your visit online. A doctor visit has the same price for every age, with a full refund if the clinic can’t see you. Visiting Puerto Rico? We see you too: see care for visitors.
How to prevent ciguatera in Puerto Rico
According to the CDC, cooking, freezing, pickling, salting or smoking fish does not destroy the toxin. The FDA adds that fish caught side by side can carry very different toxin levels. What helps:
- Never eat barracuda or moray eel: the CDC calls them high-risk.
- Avoid large reef fish, especially those over 5 pounds.
- Do not eat the head, intestines, liver or roe of reef fish, which concentrate the toxin.
- Ask local fishers and fish markets which species and areas they avoid.
How we care for you
We evaluate, diagnose and treat; if needed, we give you a lab order for a lab near you.
We see adults and children of all ages. Patients under 21: a parent with patria potestad (parental authority) or a legal guardian is on camera for the whole visit and shows photo ID.
Real-time video visit. We send you a secure video link. It works on your phone, tablet or computer.
If appropriate, the doctor prescribes and we send your prescription to your pharmacy.
You must be physically in Puerto Rico during the visit (visitors, tourists and cruise passengers are welcome).
In an emergency, call 911.
Frequently asked questions
How soon do ciguatera symptoms start?
Does cooking the fish get rid of ciguatera?
How long does ciguatera last?
Is there ciguatera in Puerto Rico?
Is ciguatera dangerous?
What should I avoid after ciguatera?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-11