Fish fillets of various species and from different sources are on sale on the markets: from sea fish such as grouper and flounder to freshwater fish such as African perch and pangasius (a sort of large catfish, mainly bred in the Mekong delta). What they have in common is the difficulty for the consumer to recognize the fish, because they are pieces of pulp without skin or head, fins, spines or other parts that can allow their identification and real freshness.

This difficulty means that the fish fillets are sometimes sold with the denominations "of convenience": currently more than 1 million tons of pangasius are produced in the farm, whose fillets, which have very low costs, are illegally marketed as the finest meats. Almost all of the fillets are obtained from large fish processed on the fishing site, often vacuum packed, frozen and shipped to wholesale markets.

These fish do not live in the Italian seas and are not caught by our fishermen. In fact, large fish caught in Italy are generally not frozen, because they would lose value (frozen fish has lower prices than fresh fish) and are sold in pieces with the skin on: an important "detail" to be taken into consideration by the the moment of purchase, when it is not possible to have the fish filleted at the moment, from the trusted shopkeeper.