鯉 (koi) is a type of freshwater fish belonging to the carp family. Known for their vibrant colors and patterns, they are often kept in outdoor ponds and gardens. Koi are popular in Japanese culture and symbolize good fortune, prosperity, and longevity. These fish can grow quite large, sometimes reaching lengths of over three feet. Koi are typically bred for their beauty and are often featured in Japanese gardens and traditional festivals. They require clean water and proper care to thrive, making them a favorite among fish enthusiasts and hobbyists.