A transparent shrimp, 3 cm (1.2 in), hovering in the mouth of a cave with red and white banded legs and a scatter of red spots on the back. Groups of a dozen hang in the water together, which is unusual for a shrimp - almost everything else in the family sits on rock.
They advertise by dancing. When a client fish approaches, the shrimp rock the body rapidly back and forth, and experiments have shown the dance is a real signal: shrimp dance more when they are hungry, fish choose dancing shrimp over still ones, and the dance rate predicts whether a fish will stop.
Cleaning is the trade - parasites, dead tissue and mucus taken off fish that hold still and open their mouths and gills for it. Client fish return repeatedly to a station and appear to remember it.
The transparency is protection. A shrimp hanging in open water at a cave mouth is exposed to everything hunting there, and being nearly invisible is what makes the position survivable, along with a truce that even hunting predators observe while being cleaned.
- glass-clear body with red and white bands on the legs and a red-spotted back
- hovers in open water at a cave mouth rather than sitting on the rock
- rocks its body back and forth when a fish approaches
- length up to 3 cm
