- Shark
- Swordfish
- King mackerel
- Marlin
- Orange roughy
- Bigeye tuna
The exact recommendations depend on the species and country.
This does not mean people should stop eating fish.
Fish provides valuable nutrients, including high-quality protein and, in many species, omega-3 fatty acids.
The practical approach is to choose a variety of fish and follow local or national recommendations concerning high-mercury species.
What About Parasites?
Parasites are another reason fish should be handled correctly.
Some wild fish can naturally harbor parasites.
This does not necessarily mean the fish is unsuitable for consumption.
Appropriate cooking can destroy many parasites, while specific commercial freezing procedures are used for some fish intended to be eaten raw.
However, not every home freezing method should be assumed to make raw fish safe.
If you're preparing sushi, sashimi, ceviche, or another raw-fish dish, the fish should come from a reputable source specifically suitable for that purpose.
Why Cleaning Fish Properly Matters
Before cooking a whole fish, it is generally important to clean and prepare it correctly.
Depending on the species and preparation method, this can include:
- Removing the scales when appropriate.
- Removing the internal organs.
- Removing the gills if required.
- Rinsing or cleaning the fish according to safe food-handling practices.
- Preventing raw fish juices from contaminating other foods.
- Cooking the fish thoroughly.
A clean preparation area is also important.
Use separate utensils or cutting boards for raw seafood and ready-to-eat foods when possible.
After handling raw fish, wash your hands, utensils, and food-contact surfaces thoroughly.
Don't Rely on Appearance Alone
A common misconception is that you can always determine whether fish is safe simply by looking at it.
Unfortunately, dangerous microorganisms don't necessarily make food look rotten.
Fish can sometimes contain harmful bacteria without obvious changes in color or appearance.
Likewise, an unpleasant smell can indicate spoilage, but the absence of a bad smell does not guarantee safety.
That's why temperature control, proper storage, hygiene, and cooking are more reliable than visual inspection alone.
What If the Fish Has an Unusual Smell?
Fresh fish generally has a mild, clean smell.
A strong ammonia-like, sour, rancid, or otherwise unpleasant odor can be a warning that the fish is deteriorating.
Other signs of spoilage can include:
- Slimy surface
- Discoloration
- Soft or deteriorating flesh
- Strong unpleasant odor
- Damaged packaging
- Improper refrigeration
When in doubt, don't taste the fish to determine whether it is safe.
If seafood appears spoiled, throwing it away is safer than taking a chance.
What About the Material Shown in the Viral Image?
The image appears to show numerous small objects inside the fish's mouth.
However, the photograph itself cannot establish what those objects are.
They could represent sediment, gravel, food material, or something deliberately placed there for the photograph.
There is also no reliable information in the image identifying the species, location, date, seller, or laboratory testing results.
Therefore, claims that the fish is contaminated with a dangerous substance—or that experts have advised everyone to stop eating it—should not be accepted simply because the photograph looks disturbing.
This is especially important with viral social-media health posts.