Goldfish
金魚 kingyo

The leading summer motif: goldfish in a glass bowl or pond look cool on a hot day, recalling the goldfish sellers and goldfish scooping of Edo summers. The gold in its name also makes it a wish for wealth and good luck.
China; by Edo tradition goldfish reached Sakai in 1502
Goldfish were bred in China and, according to the Edo breeding manual Kingyo sodategusa (1748), first reached Japan at Sakai around 1502. They stayed a luxury until mid-Edo fish farms made them cheap; by the Bunka and Bunsei eras (1804-30) goldfish sellers and goldfish scooping were part of every Edo summer, and the fish swam across ukiyo-e, fans, toys and yukata.
Worn on yukata and printed on tenugui and furoshiki for summer, for a cool look; the 金 (gold) in the name is read as a wish for money and luck.