Grayling is a type of fish belonging to the family Thymallidae. They are primarily found in cold, clear rivers and lakes across Europe, Asia, and North America. Known for their distinctive grayish-blue coloration and long dorsal fin, grayling are popular among anglers for their fighting ability and delicate flavor. These fish typically feed on insects and small invertebrates, making them an important part of the aquatic ecosystem. Grayling are also sensitive to pollution, which makes them indicators of water quality. Conservation efforts are in place in some regions to protect their habitats and ensure their populations remain stable.