Billy is a short lime green parrotfish and a main citizen of Bikini Bottom with red lips and a light orange shirt with a red stripe on it. He is Evelyn's son. He makes other brief appearances than roles in some episodes.
Billy is a lime green colored fish with orange-red colored lips. He also wears a light orange t-shirt with a red stripe on it. Billy also has a light green dorsal fin, and has light orange stripes.