Pale, with a scarlet stripe down the back split by a fine white line, and two white antennae far longer than the body. It lives at a fixed address under an overhang and waves those antennae at everything that passes, which is an advertisement.
The advertisement works. Fish queue at a cleaning station, hold still, spread their fins and open their gill covers, and the shrimp walks over them removing parasites, dead skin and bits of damaged tissue - including inside the mouth of predators that would eat it anywhere else. Both sides observe the truce, and a station that stops operating measurably raises parasite loads on the fish around it.
They are honest cleaners, which is worth saying because not all are. Some cleaner fish cheat by taking a bite of healthy mucus; this shrimp appears not to, and client fish will return to a shrimp station repeatedly.
Every adult is both sexes at once. A pair takes turns: one broods eggs on its swimmerets while the other fertilizes them, and they swap roles at the next molt, which means any two shrimp that meet can breed without any of the searching a separate-sex animal has to do.
- pale body with a broad scarlet band down the back, edged and split by white lines
- very long white antennae, waved constantly at passing fish
- always at the same spot on the reef, usually under an overhang
- length up to 6 cm
