He is a light blue and turquoise fish who wears red-orange shorts. He has blue lips, blue arms and legs, and a blue fin. A bikini-wearing version appears alongside him in the episode "SpongeGuard on Duty." That version also appears in the episode "Extreme Spots."
He seems to be fond of eating Krabby Patties since he is a regular customer at the Krusty Krab. He also appears to be fond of magic because in the episode "Hocus Pocus," he stars in a commercial for Mr. Magic's Magical Kit and seems to enjoy the product. He even appears as a magician in "My Leg!". He also appears to get easily offended when others insult his eating habits as shown in "To SquarePants or Not to SquarePants" where he got offended and angry about SpongeBob commenting about him having too many triple Krabby Patties with cheese.
He starts making fun of SpongeBob with a long insult acknowledging his infantile habits before the other customers cut him off for going on.
"To SquarePants or Not to SquarePants"
He tries to order a Krabby Combo but Squidward does not let him. He then tries to order a Double Krabby Patty but SpongeBob does not let him either. He finally tries to order a Triple Krabby Patty with cheese and SpongeBob tells him that he thinks he had too many of those, causing him to get angrily offended and leave.