Bolivian Cachibachi

Isn't this the coolest thing? My husband brought it back from Bolivia for me on his last trip there. It's an antique Bolivian pin. I'm not sure if it's silver or pewter, but I love the design. I would love to find out when it was made, and what the symbolism of the design means. Can you see the peacock on top? The fish is fashioned in a way that lets it move or wobble.
I believe it was probably worn by cholitas (the women who dress in the traditional manner with shawls and bowler type hats...and are considered indigenous.)
They probably pinned this to a shawl, and wore it on important occasions.