From Trader Vic's Website:

"In Japanese, koi sounds like the word that means 'affection' or 'love'; koi are therefore symbols of love and friendship in Japan.

Created by our in-house artist, Javier, his inspiration was drawn from the carved wooden 'Koi' fish seen in our restaurants worldwide.

Capacity 2 Fluid Ounces."

There is also a larger full-size version of this mug.