Taiwan’s “toxin-free godmother” Tan Dun-ci reveals her four favourite affordable fish, warns against large predators, and shares a salmon-skin trick that cuts heavy metal intake by nearly half.
Hong Kong – For many households, fish is the gold standard of lean protein. But a trip to the wet market or supermarket aisle can feel like navigating a minefield: Which species are safest? How do you avoid heavy metals? Taiwan’s renowned health educator and toxicology expert Tan Dun-ci, often dubbed the “toxin-free godmother,” has shared her tried-and-tested rules for choosing and cooking fish—and her advice is refreshingly simple.
Speaking recently on the Taiwanese programme Focus 2.0, Tan distilled decades of food safety knowledge into one guiding principle: “If it doesn’t fit on your plate, don’t buy it.” In other words, prioritise small, whole fish where you can see the head and tail. These species sit lower on the marine food chain, meaning fewer accumulated toxins.
Four Superstars of the Fish Counter
Tan singled out four affordable yet nutrient-dense fish that deliver exceptional value for money:
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Mackerel (鯖魚) – A single fillet packs over 4,000 milligrams of Omega-3, roughly eight times the recommended daily adult intake of 500 milligrams. “Eat mackerel regularly and you can practically skip fish oil supplements,” Tan joked.
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Pacific Saury (秋刀魚) – Rich in nutrients, but Tan cautions against consuming the internal organs, which can impart bitterness. Her tip: while the fish is half-thawed, remove the head, tail, and innards, and rinse away the bloody line. A slow soy-braise softens the bones for easier eating.
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Taiwan Tilapia (台灣鯛) – Inexpensive, widely available, and mild-flavoured, this is Tan’s pick for everyday family meals and a reliable source of high-quality protein.
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Capelin or Shishamo (柳葉魚) – Loaded with Omega-3, but Tan recommends baking it at a low 130°C or below to avoid forming harmful compounds at high temperatures.
The Salmon Skin Rule: Cut Before You Cook
Salmon may be a beloved staple, but Tan warns it comes with a hidden cost: heavy metals like methylmercury tend to accumulate in the skin and fatty layers. Her advice: remove the skin before cooking, not after.
“If you cook the salmon with the skin on and peel it off later, you only reduce heavy metal exposure by about 20 percent,” she explained. “But if you skin it before it hits the pan, you cut exposure by roughly 40 percent.” It’s a small step with a significant impact on long-term health.
Avoid These Large Predators
Lurking at the top of the oceanic food chain, large predatory fish accumulate the highest concentrations of mercury and other contaminants. Tan advises steering clear of:
- Tuna (吞拿魚)
- Marlin (旗魚)
- Shark (鯊魚)
- Oilfish (油魚)
Instead, she reiterates: choose smaller, younger fish that a standard dinner plate can comfortably hold.
Smart Shopping: Time and Temperature Matter
Beyond species selection, Tan highlights two practical habits for safer seafood consumption.
The “last item” rule. When grocery shopping, pick up all your dry goods, produce, and pantry staples first. Grab seafood only at the very end of your trip, pay quickly, and head straight home to refrigerate. This minimises the time fish spends in the “danger zone” where bacteria multiply.
Beware of marked-down meat. While discounted “sell-by-today” fish can be a thrifty, waste-reducing choice, Tan warns shoppers to inspect packaging closely. “Never buy fish with visible blood or watery liquid seeping from the packaging,” she said. That’s a red flag for spoilage, regardless of how deep the discount is.
A Simple Fix for Packaged Grouper
If you’ve purchased vacuum-sealed grouper, Tan offers a quick pre-steaming hack: pour boiling water over the fish briefly before cooking. This “blanching rinse” removes surface impurities and reduces the fishy odour, resulting in cleaner, sweeter-tasting flesh.
The takeaway? You don’t need exotic or expensive fish to eat well. By choosing smaller species, prepping them wisely—especially skinning salmon before cooking—and shopping smart, you can enjoy seafood’s many nutritional benefits while minimising your exposure to contaminants. As Tan puts it, “Good health starts long before the pan hits the stove—it begins at the fish counter.”