In a tributary of the Amazon, a monster – half-man, half-fish – is captured and placed in a reservoir in a Florida national park to be observed by scientists.
Directed by
Jack Arnold
Clint Eastwood
Jennings (uncredited)
Robert B. Williams
George Johnson
John Agar
Prof. Clete Ferguson
Dave Willock
Lou Gibson
Diane DeLaire
Miss Abbott (uncredited)
Brett Halsey
Pete (uncredited)
Bert Stevens
Search Party Member (uncredited)
Nestor Paiva
Captain Lucas
Don C. Harvey
Mac - Spotlight Party Leader (uncredited)
Bill Baldwin
Patrol Boat Dispatcher (voice / uncredited)
Robert F. Hoy
Charlie (uncredited)
Charles Cane
Police Captain
Lori Nelson
Helen Dobson
John Bromfield
Joe Hayes
Grandon Rhodes
Jackson Foster
Loretta Agar
Woman on Boat (uncredited)
Jere Beery
Photographer (uncredited)
Ricou Browning
The Gill Man (in water) / Lab Technician (uncredited)
Mike Doyle
Cop (uncredited)
Jack Gargan
Skipper (uncredited)
Charles Gibb
Cop (uncredited)
Tom Hennesy
The Gill Man (on land) / Marineland Diver (uncredited)