Why catfish is the dirtiest fish?

Catfish are indeed omnivores. Its main foods include aquatic insects and organic debris. It also eats live animals, such as animal droppings, small fish and mice. However, in aquaculture, animal manure is a cheap and non-toxic natural fertilizer. As long as it is handled properly, there is no problem. In other parts of China, the information of feeding catfish with swill or animal carcasses and viscera has been found many times. Catfish themselves love to eat this rotten thing, and most of the artificially cultured catfish grow up in this environment.

Catfish are tenacious and can survive in very dirty environments, such as urban sewers. Some people say that catfish is dirty because of its internal organs. Because it can survive in human feces, some fish farmers deliberately feed them with human or pig feces. Living in a harsh environment for a long time, catfish are prone to accumulate toxic substances, such as heavy metals, which cannot be eliminated no matter how high-temperature cooking.

As an economical and environmental-friendly natural fertilizer, manure is widely used in aquaculture besides planting organic vegetables, providing a lot of nutrition for plankton in water. Because there are a lot of parasites and pathogenic bacteria in the feces, it can't be directly poured into the pond for use. Before use, it needs to be fermented to kill parasites and pathogenic bacteria, and decompose macromolecular protein in feces into micromolecule protein and easily available nutrients. Fermented feces will not be fermented for the second time in the pond, and the anoxic gas produced by excessive consumption of dissolved oxygen in water during the decomposition of organic matter by fish is also avoided. It is not worth the loss to discharge feces directly into the pond, which can easily lead to hypoxia, illness and even death of fish. There are many catfish with big mouths in the rumor article. They are exposed to water because there is no oxygen in fecal water, and they need to swallow air to supplement oxygen instead of eating shit. ...

We can't deny the innocence of all catfish just because of a bad situation. No matter how big the catfish is, its fighting capacity is limited. If it is allowed to live in water polluted by various pathogenic bacteria (rumored excrement and garbage), it will get sick, and once it gets sick, it will easily die. Farmers are not stupid. Who raises fish to kill the fish ~ ~ Although catfish also live by eating corrosion, there are still ... eels, hairy crabs, crayfish and so on, so there is no need to be particularly nervous, as long as the production process.

However, as an omnivore, catfish still eats meat, which is in a higher position in the food chain, and it is indeed easier to enrich some harmful substances. This is a problem for all large animals and an inevitable result of the food chain. The good news is that from the current data, most of the catfish sold in the market are farmed fish, and basically no toxic and harmful substances such as heavy metals and pesticide residues exceed the standard, so they can still be safely eaten. However, the supervision of cultured fish should not be relaxed, and the management of industrial sewage discharge should be strengthened.