Seaman Tony Piccolo

Tony Piccolo joined the crew in season two as part of the show's turn toward genetic engineering storylines: a wisecracking ex-con with surgically implanted gills. Initially Lucas's obnoxious new roommate, he became one of his closest friends, and his gills made him the boat's go-to diver for missions no one else could survive.

Michael DeLuise stayed with the show through the series finale.