Sheldon (fish) (The Life of SpongeBob SquarePants)

Sheldon is a gray fish with a purple fin and purple hands who is also a citizen of Bikini Bottom. He usually wears a red Speedo.

Biography
He makes his first appearance in the season 1 episode "Sandy Goes a-Writin'", in which he is shown as one of the customers who abandon the Krusty Krab for the Chum Bucket after reading the preface to Sandy's book The Horrible Condition of Bikini Bottom's Employees, written by Plankton, who serves as the book's printer and distributor, without Sandy's permission; the customers later return to the Krusty Krab after Sandy and SpongeBob confront Plankton at the Chum Bucket and urge everyone to ignore the "Chum Bucket propaganda".