This type of high relief metal work is called Repousse. Styles like this have been made for centuries but only by very skilled artisans predominantly in Europe.
This large silver metal koi fish is a work of art and it was made for one purpose - to hold a single cloth napkin, or two, for a fancy table setting. It is not something many people had or saw and typically people didn't own big sets for 6 to 12 people. They only had 2 or 4 for small, quaint luncheons and dinners, and usually they had different animals. The European pieces like this one are triple-plate or quadruple silverplate of excellent quality.
This curved koi fish is signed inside Modello Despositato which means trademark in Italian. It is also signed with the makers mark that is a design with a capital letter A. I dont think anyone really knows who made this piece but it is commonly called Godinger as it was imported by Godinger. Today, this shiny silver repousse work of art serves as an attractive display along with a tropical motif or a fishing motif arrangement with other items. It does not have to be anything but a great work of art to look at.
The koi fish is 9" long x 4" tall. The entire piece is in excellent clean condition with no imperfections such as dents, scratches, cracks or repairs. It has been kept in my glass hutch cabinet for the past 40 yrs.