In most episodes, he appears as a greenish-brown colored fish with light tan fins and black eyes. He wears brown pants and a black belt with a gold colored belt buckle. Fred also tends to appear blue in some episodes, and rarely as a lavender color as well.
Fred first appears in "Reef Blower" in a boat that zooms by SpongeBob. He and Harry are the first two background characters to appear on the show. Fred's name is revealed in the episode "Patty Hype," where he is advertising the Shell Shack's talking and singing dog.
Fred is also known to be the character who says "DEUUAEGHH!" in the episode "Something Smells." He is famous for the running gag in which he screams his catchphrase, "My leg!", when something such as an explosion takes place. He first says it in the episode "Boating School."