Electric/Disco Clam

A very strange clam of around 4-5 cm width, easy to see them once you know where they have 'anchored' themselves, usually in crevices and caves.
They will flash the 'light' continuously unless disturbed, then they will 'close' their mantle.
It is not easy to get pictures of them flashing (bluish colour in the pictures) as they keep flashing, so have to try your luck and keep taking as many pictures as possible.
Recent studies on them have shown they use the flashing lights to attracts preys, as once they settled down in place, they don't seems to move anymore. And to defend themselves against predators since they don't move, studies have found high levels of sulfur in the clam’s tentacles, which they used to repulse approaching predators.