Subject: A Day Octopus (Octopus cyanea) wriggles its eight arms independently but synchronised. Not sure if he tries to communicate with the Lionfish (probably Pterois muricata) that swims by and who remains quite uninterested.
Technique: To accentuate the movement of the octopus’ arms a slimy sound was added in post-production. Although water carries sounds well, it is almost impossible to hear the sound of animals underwater on video. Usually the diver’s breath is the most profound sound in the shot.