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
Robert B. Williams
George Johnson
Clint Eastwood
Jennings (uncredited)
Dave Willock
Lou Gibson
Robert F. Hoy
Charlie (uncredited)
Grandon Rhodes
Jackson Foster
Diane DeLaire
Miss Abbott (uncredited)
John Agar
Prof. Clete Ferguson
Charles Cane
Police Captain
Bert Stevens
Search Party Member (uncredited)
Brett Halsey
Pete (uncredited)
Don C. Harvey
Mac - Spotlight Party Leader (uncredited)
John Bromfield
Joe Hayes
Bill Baldwin
Patrol Boat Dispatcher (voice / uncredited)
Nestor Paiva
Captain Lucas
Lori Nelson
Helen Dobson
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)