@Neogonodactylus, do O. rubescens tend to be that nondescript white most of the time? The majority of the pictures I have seen are of them foraging our of the water where they are always very red.
The juveniles seem to display pale colors more frequently. Also, the first image above was taken as the animal was starting to jet away. Blanching when starting to escape seems to be common in many species. Here is a shot of an adult O. rubescens with more typical red coloration.
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