Pederson cleaner shrimp (Ancylomenes pedersoni)

Classification (WoRMS)

Full classification as recorded by WoRMS: Kingdom: Animalia · Phylum: Arthropoda · Class: Malacostraca · Order: Decapoda · Family: Palaemonidae · Genus: Ancylomenes.

Accepted name: Ancylomenes pedersoni · Authority: (Chace, 1958) · Taxonomic status: accepted · AphiaID: 514493.

Synonyms and superseded combinations recorded for this taxon: Ancylomenes anthophilus (Holthuis & Eibl-Eibeslfeldt, 1964); Periclimenes (Periclimenes) anthophilus Holthuis & Eibl-Eibesfeldt, 1964; Periclimenes (Periclimenes) pedersoni Chace, 1958; Periclimenes pedersoni Chace, 1958.

Source: World Register of Marine Species (WoRMS) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=514493 (CC BY 4.0). Accessed 2026-09-23.

Biology and life history (SeaLifeBase)

Measured values published by SeaLifeBase for Ancylomenes pedersoni. Only fields the database actually holds for this species are shown; these are database values, not aquarium guidance.

Depth range: 1–35 m · Habitat zone: benthic.

SeaLifeBase notes: Epibiotic (Ref. 97531). Dwells in reef habitats in Belize. Forms obligate associations with sea anemones (Ref. 128695).

Source: SeaLifeBase species summary (SpecCode 24495) — https://www.sealifebase.se/summary/Ancylomenes-pedersoni.html (CC BY-NC 3.0 — non-commercial use only). Accessed 2026-09-23.

Distribution and occurrence records (GBIF)

3,410 georeferenced occurrence records for Ancylomenes pedersoni are published through GBIF from 32 countries or marine areas. The map above plots 104 distinct locations from a sample of 3,000 records, omitting 13 inland records that carry an institution's coordinates rather than a collection site; it shows where the species has been observed and reported, not a modelled range.

Most records by country or area: Puerto Rico (1,979); Guadeloupe (346); United States of America (203); Martinique (133); Bonaire, Sint Eustatius and Saba (129).

The full country table, WoRMS marine regions and the sampling notes are on this species' Distribution page.

Source: GBIF Occurrence Search (taxonKey 6456679) — https://www.gbif.org/occurrence/search?taxon_key=6456679&has_coordinate=true (records CC0 / CC BY); WoRMS distribution records (MarineRegions) — https://www.marinespecies.org/aphia.php?p=taxdetails&id=514493 (CC BY 4.0); Natural Earth 110m basemap — https://www.naturalearthdata.com/ (public domain). Accessed 2026-09-23.

Description and natural history (Wikipedia)

Pederson's shrimp is a small transparent shrimp with bluish and violet markings on the body and long white antennae and within its range is unlikely to be confused with other species.

Pederson's shrimp lives in association with a sea anemone, either Bartholomea annulata or Condylactis gigantea, living among the tentacles with impunity. Before it can do this it needs to acclimatise itself to the anemone by progressively pressing its body and appendages against the tentacles for increasing periods of time. After this it is able to move between the tentacles without getting stung but if it is separated from its host for a few days, it will need to repeat the immunizing procedure. Up to 26 shrimps have been found associated with one sea anemone but usually there are just one or two. The shrimp offers cleaning services to passing fish and attracts their attention by lashing its antennae about. Fish visiting the cleaning station will remain stationary while their external parasites are removed and eaten by the shrimp, which even cleans inside the gill covers and the mouth. If a neon goby sets up a cleaning station nearby, the shrimp will clean the client fish at the same time as the goby does. Researchers have shown that fish recognise the sea anemone Bartholomea annulata as being a place at which the shrimps' services are likely to be available. The larger the sea anemone, the more likely fish are to visit it.

Source: Wikipedia: Ancylomenes pedersoni — https://en.wikipedia.org/wiki/Ancylomenes_pedersoni (CC BY-SA 4.0). Accessed 2026-09-23.

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