Under a centimeter long, covered in hair-like filaments, sitting in a tuft of filamentous algae that it matches in color and texture. It is not camouflaged against algae; it is shaped like algae, which is a different and much better trick.
The only way to find one is to watch. Divers who photograph these work by staring at a patch of algae until part of it moves against the surge - the shrimp shifts on its own timing while the weed moves with the water, and that mismatch is the entire search image. Guides who can do this reliably are worth their fee.
Color follows the host. Animals on red algae are red, on green algae green, and an individual that changes patches changes over subsequent moults - so the same species photographed at two sites looks like two.
What it eats has barely been recorded: detritus and whatever settles on the algae, as far as anyone can tell. This is one of those animals known almost entirely from photographs rather than from study, and everything above the size and the habitat is inference.
- under a centimeter, body covered in hair-like filaments that match the algae it sits in
- color varies with the host algae: red, brown, green or yellow
- gives itself away by moving, never by being seen
- length up to 1 cm
