鮎 (ayū) is a type of freshwater fish found in rivers across East Asia, particularly in Japan. It is known for its slender body and distinctive flavor, often enjoyed in traditional Japanese cuisine. The fish typically migrates from the sea to freshwater rivers to spawn, making it a seasonal delicacy. In Japan, 鮎 is celebrated during the summer months and is often grilled or served in various dishes. It is also associated with the cultural practice of 鮎釣り (ayu fishing), where anglers catch the fish using traditional methods. The fish's unique taste and cultural significance make it a cherished part of Japanese culinary heritage.