在这第三部鳃人电影，那生物被抓住了，一个富有而疯狂的科学家成功地被它改变为空气呼吸的生物，可这让生物非常生气，后果很严重，它逃脱了，四处杀人放火。
Rex Reason
Dr. Thomas Morgan
Jeff Morrow
Dr. William Barton
Leigh Snowden
Marcia Barton
Gregg Palmer
Jed Grant
Maurice Manson
Dr. Borg
James Rawley
Dr. Johnson
David McMahon
Capt. Stanley
Paul Fierro
Morteno
Lillian Molieri
Mrs. Morteno
Frank Chase
Steward
Larry Hudson
State Trooper
Ricou Browning
The Gill Man (in water)(uncredited)
Don Megowan
The Gill Man (on land)(uncredited)
George Sowards
Ranch Hand (uncredited)
