A near-transparent cleaner shrimp on anemones, hard to separate from Holthuis's shrimp.
A shrimp to about 3 cm, the body almost entirely clear with a scatter of small opaque white spots along the back and abdomen, white tips to the claws and fine violet lines on the tail fan. There is no saddle and no bold outlining, which is the quick separation from the magnificent and graceful anemone shrimps. The real problem is Ancylomenes holthuisi, which shares the hosts, the size and the general look; the two are told apart on the arrangement of the white markings on the carapace and on the teeth of the rostrum, neither reliably visible in the water, and a fair proportion of field records of one are probably the other. It was described in Periclimenes and moved to Ancylomenes, and both names remain in use.
It lives on large host anemones — Heteractis, Stichodactyla and Entacmaea — and also on bubble coral and mushroom corals, so the host is the search image rather than the shrimp. It is a working cleaner: it holds a position on the oral disc or at the edge of the host, waves its antennae at passing fish, and services those that stop, including fish considerably larger than itself. Anemones that hold anemonefish frequently hold this shrimp as well, along with the porcelain crab, and one host can carry all three.
A shrimp at a cleaning station is used to being approached and is among the easier commensals to work with, provided the anemone is not touched — a contracted anemone takes the shrimp down with it. Recorded from about 3 to 30 m.
Ratings are per location: 1 means found on most dives that look for it, 5 means a handful of records. Where enough dives have been logged the figure is calculated from them; otherwise it is an editorial estimate, and says so. We publish habitat and destination, not the dive site.