Fishlegs is a character in the "How to Train Your Dragon" franchise. He is a friendly, smart, and lovable Viking with a big heart who loves dragons as much as the protagonist Hiccup does. Fishlegs is known for his vast knowledge about dragons, carrying a big book like a dragon encyclopedia that helps him identify and understand different types of dragons. Although he may be a bit nervous and sometimes clumsy, Fishlegs supports Hiccup in training dragons with his knowledge and proves that courage comes in many forms. He is a symbol of kindness, learning, and bravery through friendship in the story.

Fishlegs is often the dragon stats expert among the young Vikings and tends to be ignored by others, but his optimism and passion for dragons make him an important friend and ally. In the live-action remake of the film, Fishlegs is portrayed by actor Julian Dennison.

In summary, Fishlegs is a key friend and dragon expert alongside Hiccup, helping with dragon training by using his knowledge, kindness, and bravery throughout the "How to Train Your Dragon" stories.