Are These 4 Types of Fish "Cancer-Causing"? The Truth Lies in How They're Grown, Processed, and Cooked — Not the Fish Itself.

“These 4 types of fish are on a cancer list — eating them often will definitely cause cancer!” Recently, such alarming health posts have spread widely on social media, putting commonly eaten fish such as salted fish, catfish, hairtail (ribbon fish), and basa fish under a cloud of suspicion. After reading these claims, many people have become worried, some even avoiding fish altogether. But is this really true?

Authoritative organizations like the International Agency for Research on Cancer (IARC), part of the World Health Organization, and China's food safety authorities have clearly stated: No fish is inherently carcinogenic. The so-called "cancer list" essentially refers to health risks that arise from the farming, processing, cooking, or storage of certain fish — not from the fish itself. Fish is an important source of high-quality protein and unsaturated fatty acids. The Dietary Guidelines for Chinese Residents (2022 Edition) explicitly recommends eating fish 2–3 times a week. Blindly avoiding fish may be detrimental to health. This article will break down the four types of fish rumored to be "carcinogenic," clarify the real sources of risk, and provide practical eating guidelines.

1. Chinese Salted Fish: The Only Proven Category 1 Carcinogen — Risk Lies in the "Curing Process"

Among the rumored list, salted fish is the only type explicitly classified by an authoritative agency as carcinogenic. In 2012, the IARC listed Chinese-style salted fish as a Group 1 carcinogen — the same category as tobacco, alcohol, and formaldehyde. This is a key basis for the "fish causes cancer" claim. However, it must be made clear: the carcinogenic risk of salted fish comes entirely from the traditional curing process, not the fish itself.

Chinese-style salted fish is made through heavy salting, sun-drying, and brief fermentation. This process can generate known carcinogens — nitrosamines. Fish is rich in protein, and during salting, protein breaks down into amines, which react with nitrites introduced by the salt, eventually forming nitrosamines. Additionally, the high-salt environment can damage the mucosal barriers in the mouth and stomach, reducing the body's ability to metabolize carcinogens — a dual factor that increases cancer risk. Epidemiological studies show that people who consume large quantities of Chinese-style salted fish frequently over the long term have an increased risk of nasopharyngeal cancer (up to 1.8 times higher) and significantly elevated risks of stomach and esophageal cancer. This is particularly relevant in areas of China with high nasopharyngeal cancer incidence, where salted fish consumption is strongly linked to disease risk.

This doesn't mean salted fish should never be eaten. IARC's conclusion is based on "long-term, high-volume, frequent intake." An occasional treat (e.g., once or twice a month, no more than 50 grams per serving) allows the body's metabolic system to handle minimal risk — no need for excessive panic. The real caution should be directed at dietary patterns involving "regular weekly consumption of over 50 grams" and low-quality salted fish of unknown origin or insufficient curing time — such products may contain nitrite levels several times above limits, significantly increasing risk.

2. Catfish: Risk Lies in "Irregular Farming" — Safely Sourced Catfish Is Fine to Eat

Catfish made the "cancer list" based on stereotypes like "bottom-dwelling fish, tolerant of pollution, prone to accumulating harmful substances," and is even mistakenly called a "trash fish." In fact, catfish itself is a high-protein, low-fat quality fish. Its potential risk comes only from non-standard farming practices.

Catfish tolerate low-oxygen environments and are omnivorous, making them suitable for intensive farming. Some small-scale farmers, in pursuit of high yields and lower mortality rates, may illegally use banned substances such as malachite green and nitrofurans. Malachite green is highly toxic, persistent, and classified as a Group 1 carcinogen; long-term intake can increase the risk of liver and bladder cancer. Nitrofuran metabolites are also carcinogenic and teratogenic and were banned for aquaculture in China as early as 2002. Additionally, if farming waters are contaminated by industrial waste, catfish, as bottom-dwellers, may accumulate heavy metals and polychlorinated biphenyls (PCBs), posing health risks with long-term, high consumption.

However, with increasingly strict standards for drug residue testing in China's aquaculture industry, catfish sold through formal channels (large supermarkets, compliant farmers' markets) must pass drug residue and heavy metal testing to meet food safety standards. Consumers simply need to avoid unusually cheap catfish of unclear origin, check that the fish body is smooth and odor-free with firm flesh when buying, and ensure it is thoroughly cooked — then it is safe to eat.

3. Hairtail (Ribbon Fish): Risk Lies in "Storage and Cooking" — Steaming or Braising Is Far Better Than Deep-Frying

Hairtail, a common household dish, is rumored to be "carcinogenic" mainly for two reasons: improper frozen storage and high-temperature frying as a cooking method — neither relates to the fish itself.

Hairtail is mostly sold frozen. If it undergoes repeated thawing and refreezing during transport or storage, the fish can spoil, breeding bacteria and producing nitrites. Nitrites can combine with amines in the body to form nitrosamines, increasing carcinogenic risk. More caution is warranted regarding cooking methods — many people enjoy coating hairtail in batter and deep-frying it. High-temperature frying (above 180°C/356°F) can generate heterocyclic amines (HCAs) and polycyclic aromatic hydrocarbons (PAHs) in the fish. Both are classified by IARC as Group 2A carcinogens, and long-term, high intake can increase the risk of colorectal and stomach cancers. Research from Brown University also confirmed that people who eat deep-fried fish fillets more than twice a week have a 28% higher risk of colorectal cancer, whereas no such risk exists with steamed or boiled fish.

The key to mitigating risk is "proper storage + healthy cooking": buy frozen hairtail from reputable sources, store it sealed in the refrigerator or freezer at home, and avoid repeated thawing and freezing. When cooking, prioritize steaming, braising, or stewing. If you prefer frying, control the oil temperature, avoid burning the fish, and do not reuse oil multiple times. Eating properly handled hairtail once or twice a week provides nutritional benefits while keeping risks in check.

4. Basa Fish: Rumors Stem from "Early Irregular Practices" — Legally Imported Basa Is Safe

Basa fish, known for its tender texture, lack of small bones, and affordable price, has become popular in hot pots and fast-food dishes. However, being a "foreign species" and low-priced has led to suspicions of "hormone farming and excessive antibiotics causing cancer." In reality, the "cancer rumor" about basa fish originated from early irregular farming practices by some operators. Currently, basa from formal channels poses controllable risks.

Basa fish originates from Southeast Asia. Early on, some farms in Vietnam, dealing with disease issues in high-density farming, illegally used industrial antibiotics, damaging its reputation. However, China now implements strict customs inspection and quarantine protocols for imported basa fish. All legally imported basa must pass multiple tests for drug residues, heavy metals, and microbes, complying with China's food safety standards. The claim that "basa fish are fed hormones" is unfounded — hormones are costly and can cause deformities in fish, so legitimate farmers do not use them.

When buying basa fish, choose products with intact packaging labeled "import inspection and quarantine qualified." Avoid unpackaged basa of unclear origin. Cook it thoroughly to kill potential microbes and break down trace harmful substances — then it can be eaten with confidence.

Core Summary: Avoid 3 Major Risks — 4 Principles for Safe Fish Eating

In summary, the claim that "these 4 types of fish cause cancer" essentially misinterprets the "source of risk." Fish itself is a healthy food. The real carcinogenic risks come from the "curing process, irregular farming, improper storage, and high-temperature cooking." To enjoy fish safely, just follow these four principles:

1. Choose the Right Source: Prioritize Formal Channels, Avoid Products of Unknown Origin
   When buying fish, choose large supermarkets, chain farmers' markets, or reputable e-commerce platforms. Check for product inspection and quarantine certificates and origin labeling. Avoid fish that are unusually cheap, have an odd smell, loose flesh, or abnormal color (e.g., excessively pale or greenish) — such products likely have farming or storage issues.

2. Choose the Right Cooking Method: Low-Temperature Methods First, Avoid High Heat and Charring
   Prioritize low-temperature cooking methods like steaming, boiling, braising, stewing, or making soup. These preserve nutrients and avoid generating carcinogens like HCAs and PAHs. If you choose frying or grilling, control the oil temperature (not exceeding 180°C/356°F) and cooking time to avoid charring, and don't consume such preparations frequently.

3. Control Frequency: Moderate Intake, Avoid Long-Term Monotony
   Follow the Dietary Guidelines for Chinese Residents recommendation: eat fish 2–3 times a week, with each serving about 100–150 grams (roughly half a small bowl of fish meat). Avoid long-term, exclusive consumption of any single type of fish, especially salted fish or large predatory fish (which may accumulate heavy metals). Diversifying your intake helps spread potential risks.

4. Special Populations: Targeted Choices to Reduce Risk
   Pregnant and breastfeeding women, as well as children, should avoid large predatory fish high on the food chain (like shark, swordfish, and bigeye tuna), which may accumulate mercury and affect nervous system development. Instead, choose low-mercury fish such as perch, cod, and salmon. People with compromised immune systems should ensure fish is thoroughly cooked and avoid raw fish preparations (e.g., raw freshwater fish may carry liver flukes, and long-term infection can increase liver cancer risk).

Conclusion: Don't Let Rumors Deprive You of the Benefits of Eating Fish

In an age of widespread health anxiety, "food causes cancer" rumors easily stir panic. However, we need a rational perspective — the carcinogenic risk of most foods is closely tied to "dosage, method, and source," not the food itself. Fish is an exceptionally cost-effective healthy food with clear benefits for cardiovascular health and brain development. Blindly avoiding fish due to rumors means missing out on valuable nutrition.

Remember: There are no "carcinogenic fish" — only "carcinogenic ways of eating and problematic fish." As long as you choose the right source, cook properly, and consume in moderation, you can safely enjoy the nutrition and flavor of fish without being swayed by online "cancer lists."

Authoritative References:

• International Agency for Research on Cancer (IARC), List of Carcinogens and related evaluation reports

• Chinese Nutrition Society, Dietary Guidelines for Chinese Residents (2022 Edition)

• Ministry of Agriculture and Rural Affairs of China, List of Veterinary Drugs and Other Compounds Prohibited in Food Animals

• Brown University epidemiological research report (2025)

• China News Service investigation report on carcinogen addition in aquaculture and transport links (2025)

This article is curated from external sources and published by CHN Healthcare Network. The views expressed do not necessarily reflect the platform’s position. For copyright concerns regarding content or images, please contact us at info@healthcarechn.com for prompt resolution.