Amphibian Man

Amphibian Man is a 1962 Soviet science fiction romance film starring Vladimir Korenev. The adopted son of a doctor/scientist who was sometime in the past forced to save the boy's life by implanting him with shark gills. Thus he is able to live under water, but must keep his secret from the world.

Doctor Salvator performed surgery on his son and now young Ichtiandr can live underwater. This gives him certain advantages, but creates a lot of problems.