Amphibian Man (1962)

aka’s: Chelovek-Amfibiya/
Человек-Амфибия

People living at the seashore town are frightened by reports about the unknown creature called the “Sea Devil.” Nobody knows what it is, but it’s really a son of a Doctor Salvator (Nikolai Simonov). The doctor performed a surgery on his son (Vladimir Korenev) and now young Ihtiandre can live under water. This gives him certain advantages, but creates a lot of complications which ensue. Also stars Anastasiya Vertinskaya and Mikhail Kozakov. (In Russian language with English subtitles).