Carp

Originally from Central Asia, carp spread naturally into China, then into the Euphrates basin and the Danube, between 8,000 and 10,000 years ago. The Romans introduced it into Europe, and medieval monks raised carp in their monastery fish ponds. It is a hardy fish, which facilitated its migration and acclimatisation.
It was often served exclusively to lords, and the tongue, reputedly the tastiest morsel, was always reserved for the most distinguished guests.
Carp was still considered a great delicacy in the 18th century. Grimod de la Reynière, a lawyer and gastronomic writer, wrote of a carp that swam in the King's reservoirs in Strasbourg in 1786, that had thrice been sent to Paris and returned because no-one wanted it… It was too costly!
The asking price was 25 Louis… the cost of 2,000 dozen eggs!   

A Gourmet's notebook