Koi is the Japanese word for the ornamental "carp" that swims in garden ponds, and it sounds exactly like a second Japanese word meaning "love". In Japan koi fish stand for perseverance and good fortune, and in the United States the name belongs to the wave of short nature names like Kai and Koa. Koi has climbed from number 6864 in 2015 to number 2207 in 2025, its best rank so far, with 84 girls given the name.