Is this perhaps the beginning of shedding or something else? It does not look like the scutes are lifting, other than by the vertebrae.
EDIT: I should add that you can only see it in the water when the light catches it right, which is why I'm leaning toward air under a scute. See for example, this picture taken just days earlier than the ones below viewtopic.php?f=14&t=35484
Picture in the water:

First picture out of the water:

Second picture out of the water:

Any thoughts or insight appreciated.

