Dictionary of Ichthyology  

coins = fish appear on various coins as they have long been important economically and symbolically.

Silver tetradrachm issued by the city of Cyzicus, ca. 350 B.C., showing a tuna fish below, from Wikimedia Commons: http://commons.wikimedia.org/wiki/File:Tetradrachm_
Cyzicus_350BC_reverse_CdM_Paris.jpg

Canadian Museum of Nature
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