About Ancylomenes pedersoni (Chace, 1958)
Pederson's shrimp (Ancylomenes pedersoni) is a small, transparent shrimp that has bluish and violet markings on its body and long white antennae. Within its known range, it is not likely to be confused with other shrimp species. This shrimp lives in association with one of two species of sea anemone: Bartholomea annulata or Condylactis gigantea, and can move among the anemone's tentacles without being harmed. Before it can safely live among the tentacles, the shrimp must acclimatize to the anemone by progressively pressing its body and appendages against the tentacles over increasing periods of time. After this acclimatization, it can move between the tentacles without being stung. However, if the shrimp is separated from its host anemone for a few days, it will need to repeat this acclimatization process. While up to 26 individual shrimp have been found associated with a single sea anemone, most anemones host only one or two shrimp. Pederson's shrimp provides cleaning services to passing fish, and attracts fish attention by lashing its antennae. Visiting fish remain stationary while the shrimp removes and eats their external parasites. The shrimp will even clean inside the fish's gill covers and mouth. If a neon goby establishes a cleaning station nearby, the shrimp will clean client fish at the same time as the goby. Research has found that fish recognize the sea anemone Bartholomea annulata as a location where cleaning services from Pederson's shrimp are likely available. Larger sea anemones are more likely to be visited by fish seeking cleaning services.
