Johnny Whitaker and Scott C. Kolden became buddies while shooting Disney's movie-of-the-week Mystery in Dracula's Castle (1973), and Whitaker recommended Kolden for the part on this series. The pair remained lifelong friends off-screen, spending holidays together and serving best-man duties in each other's weddings.
One day at the beach, creator Sid Krofft took notice of a mass of seaweed that had drifted near the shore. As it bounced and frolicked upon the waves, Krofft envisioned it as a living creature, so he scooped up and hauled it back to his production office, where he introduced it as Sigmund the sea monster, the star of his next TV show.
Early into the start of the second season, a light fell from the rafters onto the styrofoam cave, igniting a fire which decimated two soundstages at Samuel Goldwyn Studios. The production was delayed for 5 weeks as they recreated the sets at General Service Studios, which resulted in only 12 episodes being shot instead of the 15 that the network had contracted.
Rip Taylor (Sheldon) was in full costume with green makeup and wig, pink shorts, a cape, and flippers on his feet when a fire erupted at the studio. Everyone was dazed and confused, he couldn't hitch a ride and had to trek down Hollywood Boulevard in "fish drag" to get back to the hotel where he was staying.
Throughout the first season, Johnny Whitaker performed a song in each episode, but this was abandoned in the second season because his voice was changing.