He is a faded brown fish with a light-brown mouth and black eyes. He wears a red tank-top.
He is shown to be a kindhearted Bikini Bottomite, although he has an antagonistic streak. Like most of the other Bottomite fish, he'll join the town in civil unrest in support of certain causes. He is shown to have a distaste for boating school and isn't afraid to exhibit his rebelliousness, as he cut class an inexcusable number of times.
He also seems to be a bit emotionally sensitive, as seen when he cries upon Squidward stealing his burger and insulting him in "Le Big Switch."
He is a regular Krusty Krab customer and enjoys their Krabby Patties, and is shown to eat their food like a pig.
He seems to enjoy candy in the shape of fish, but apparently this kind of food is illegal in Bikini Bottom.
In "Le Big Switch," Squidward takes his Krabby Patty and insults him, which makes him cry.
In "Ditchin'," he gets arrested for eating Quasi-Gummy Chewy Candy Fish because it is "of his own kind." It is then revealed that he used to be a good student in boating school until he started cutting class, which lead him into criminal notoriety. This scares SpongeBob since he is doing exactly the same thing.
In the episode "Porous Pockets," it is revealed he is allergic to dairy.