He was first seen in the episode "Reef Blower." However, he is barely seen in the episode, as he was in a car as SpongeBob zoomed past him. He's most often seen dining at the Krusty Krab.
His name was revealed in the episode "Patty Hype," where he was advertising the Shell Shack's talking and singing dog.
He is voiced by Doug Lawrence. He is famous for the running gag in which he screams "My leg!" when something such as an explosion takes place. This quotation first appeared in the episode "Boating School."
Fred appeared in "Face Freeze!" as the main character of Krabs' story. He has been seen in many episodes at the movie theater. There is one episode where he does get hurt, but he says "My leg!" in a dull tone, implying that he has sustained enough injuries to not feel the pain.