Rex Reason
饰 Dr. Thomas Morgan
Jeff Morrow
饰 Dr. William Barton
Leigh Snowden
饰 Marcia Barton
Maurice Manson
饰 Dr. Borg
James Rawley
饰 Dr. Johnson
David McMahon
饰 Capt. Stanley
Lillian Molieri
饰 Mrs. Morteno
Larry Hudson
饰 State Trooper
Ricou Browning
饰 The Gill Man (in water)(uncredited)
Don Megowan
饰 The Gill Man (on land)(uncredited)
George Sowards
饰 Ranch Hand (uncredited)
