Ametaro is the father of protagonist Demetan (known as Jonathan in English adaptations), a tree frog whose family endures social exclusion within Rainbow Pond due to their species. He supports his family through his profession as a toymaker. His wife Amako (called Mrs. Hopper in English dubs) and he have at least one surviving child, Demetan, though an early series scene depicts the loss of their other offspring to predators.

Throughout all media portrayals—including the original 39-episode series, international adaptations, and the English-language films *The Brave Frog* and *The Brave Frog's Greatest Adventure*—Ametaro's family remains socioeconomically disadvantaged within the pond hierarchy, a direct result of their identity as tree frogs rather than pond frogs. He consistently appears as part of Demetan's immediate family unit. Ametaro shows no documented character evolution, backstory expansion, or distinct personal development arcs across any official seasons, movies, or regional adaptations, with his portrayal remaining focused solely on his familial role as Demetan's father within Rainbow Pond's social dynamics.