A Pup Named Scooby-Doo studio after the first season. "A Pup Named Scooby-Doo" is the final television series in the franchise in which Don Messick portrayed Scooby-Doo before his death in 1997, and one of the few in the franchise in which someone other than Frank Welker voiced the character of Fred Jones (child actor Carl Steven took on the role for this series; Welker voiced other bit roles in the series, including as Fred's uncle). Messick and Casey Kasem, the latter of whom voiced Shaggy Rogers, were the only two voice actors from other "Scooby-Doo" series to reprise their roles, and both received
Scooby-Doo and Scrappy-Doo (1979 TV series) threatening cancellation for the show, whose ratings were in decline. ABC was going to choose between two shows-Scooby-Doo or an unnamed pilot from Ruby Spears Enterprises. Therefore, for its 1979–1980 season, "Scooby-Doo" was given a major overhaul, adding the character of Scooby's nephew Scrappy-Doo, voiced by Lennie Weinrib, and changing the name of the show to "Scooby-Doo and Scrappy-Doo". Although still present in these episodes, the characters of Fred, Daphne, and Velma became less essential to the plot and Shaggy, Scooby and Scrappy were the main focus. Marla Frumkin took over Pat Stevens' role as Velma Dinkley towards the end