Recreational fishing offers a thrilling way to connect with nature, enjoy time on the water, and reel in an impressive catch.

While many fish species are safe and delicious to eat, some pose serious health risks due to toxins that can be harmful or even deadly if consumed.

Anglers must identify these potentially poisonous species to ensure their safety and that of others.

Understanding Poisonous Fish

Fish are considered poisonous when their flesh or organs contain toxins that can cause illness or death. These species can cause severe illness due to naturally occurring toxins, such as ciguatera toxin or tetrodotoxin.

These toxins may occur naturally or accumulate in the fish from their environment or diet. Understanding these toxins, the species they affect, and their symptoms can help anglers avoid dangerous mistakes.

Ciguatera vs. Tetrodotoxin: What’s the Difference?

Ciguatera Toxin

• Originates from: A type of marine microalgae called Gambierdiscus. Small fish ingest these algae, and larger predatory fish accumulate the toxin in their tissues.
• Affected fish: Usually reef fish found in tropical and subtropical waters.
• Heat stability: Ciguatoxin is heat-stable, meaning cooking, freezing, or smoking will not neutralize its effects.
• Risk level: It’s the most common fishborne toxin causing illness worldwide.

Fish Containing Ciguatera Toxin

Barracuda: Found in warm coastal waters, barracuda are known carriers of ciguatoxin, which causes ciguatera poisoning. This toxin cannot be detected through smell, taste, or cooking, making it a hidden danger. Larger barracudas are more likely to contain high toxin levels.

Surgeonfish: Popular among snorkelers for their bright colors, surgeonfish are occasionally caught by anglers.

Triggerfish: While many species of triggerfish are safe, some, like the reef triggerfish, can carry ciguatoxin. It’s always wise to consult local fishing guidelines before consuming unfamiliar fish species.

Amberjack: Large predatory fish found in tropical waters, often linked to ciguatera cases.

Grouper: Popular among anglers but can carry ciguatoxin, particularly in the Caribbean and Southern Pacific regions.

Symptoms of Ciguatera Poisoning
Ciguatera Poisoning: Nausea, vomiting, diarrhea, neurological symptoms such as tingling or temperature reversal (hot feels cold and vice versa).

Tetrodotoxin

• Originates from: Produced by certain marine bacteria and accumulates in the tissues of specific fish species.
• Affected fish: Typically pufferfish and a few other species.
• Heat stability: Tetrodotoxin is also heat-stable and remains toxic even after cooking.
• Risk level: Tetrodotoxin poisoning is less common but far more lethal, with no known antidote.

Fish Containing Tetrodotoxin Toxin

Pufferfish (Blowfish): Pufferfish is a delicacy in some parts of the world but is lethal if not prepared correctly. This toxin is found in the liver, skin, and other parts of the fish.

Recreational anglers should avoid consuming pufferfish unless it has been professionally prepared by licensed experts.

Blue-ringed Octopus: Not a fish, but this small marine creature also contains tetrodotoxin. Handle with extreme caution.

Porcupinefish: Related to pufferfish, it carries tetrodotoxin in its organs

Symptoms of Tetrodotoxin Poisoning
Rapid onset of numbness, paralysis, and respiratory distress. This can be fatal if untreated.

Seek medical attention immediately if you experience any symptoms after eating fish.

Scombroid

Scombroid poisoning occurs when certain fish are improperly stored after being caught, leading to histamine buildup.

Fish at Risk: Tuna, Mahi-Mahi, Bluefish, Mackerel, and Bonito.
Prevention: Proper icing and refrigeration after capture.

Fish Contaminated with Mercury or PCBs (Long-Term Toxicity)

While not acutely poisonous, certain fish may carry high levels of mercury or polychlorinated biphenyls (PCBs) due to pollution.

Examples:
King Mackerel
Swordfish
Shark
Tilefish

Freshwater bass, including largemouth and smallmouth bass, are popular catches in many regions, such as the Everglades. While the bass is celebrated for its excellent taste and edibility, fish caught in areas like the Everglades often have high mercury levels due to environmental contamination.

Consumption should be limited to one serving per week or less, depending on the mercury levels in the region.

Check Local Advisories: Always refer to state or regional fish consumption guidelines

Not to Be Confused with Venomous Fish: Understanding the Lionfish

Source: https://blogs.the-hospitalist.org/content/aquatic-antagonists-lionfish-pterois-volitans-0

It’s essential to distinguish between venomous and poisonous fish, as the terms describe different methods of delivering toxins. A venomous fish, like the lionfish, delivers its toxin through specialized spines or stingers, whereas a poisonous fish requires the toxin to be ingested or absorbed.

Their flesh is not poisonous, but their spines contain venom that can cause intense pain if stung.
Wear gloves when handling fish with venomous spines, and use tools to remove hooks safely.

Conclusion

Fishing is an enjoyable activity, but it’s crucial to stay informed about the risks associated with consuming certain species. By understanding the dangers of these toxins, anglers can enjoy their time on the water safely.

Use tools like FishVerify to make confident and informed decisions about your catch.

When in doubt, practice catch and release—your health is always worth it!