Ever since I first saw one of these, in the Caribbean, 15 years ago, i have wanted to see one closely.
They look like fish scales and you see them in the water column. They are tiny, about 5mm long. It takes a while to realise that they are not fish scales, but are in fact tiny creatures. I think I remember someone saying they were octopods (?) but cannot find anything about them.
We get them a lot in Lembeh. They are visible one second, as they reflect light, giving them their distinctive metallic blue colour, then they disappear. Just when I get in focus range, they always swim away, with a flick of their tails, Very frustrating.
This week I finally found a dead one! It caught my eye, as it had become attached to a tendril of something on the bottom. Finally i could see and film it's body. even when dead it still has this amazing reflective capability, almost ghost-like.
If you look very closely at the footage, especially when it disappears, you can see it's tiny legs and body.
I hope this will interest others like me, who have always wondered what it is.