Koi is a distinctive girls' name in United States, ranking #11109 in 2009 with 10 recorded births. This places Koi in the bottom 45% of ranked US girls' names for the year. Its actual usage is classified as Rare. The name reached its all-time peak in 2025 with 84 births ranking #2207. In 2009, approximately 1 in every 183,687 girls born was named Koi. RISING Recent data shows the name is currently rising.