Gus is grayish-brown in color, with black eyes. He has gray lips. He usually wears light green shorts with a dark green flower design. His shorts are similar to Patrick's.
He is first seen in "Ripped Pants," when Larry uses his volleyball to knock over him and 2 other fish. His girlfriend was Nazz-Mimi, although it is uncertain whether they are still together. He is a surfer as seen in "Pranks a Lot" as he is scared off his surfboard by the "ghosts". He is usually a happy and nice character, but can get angry at small things.
His most well-known appearance is his scene in "As Seen on TV," where SpongeBob sings "The Striped Sweater Song" about his sweater, much to his dismay. This is the only episode where Gus is seen wearing the green striped sweater.