COMMENSAL SHRIMPS
PALAEMONIDAE
Pederson Cleaning Shrimp
Ancylomenes pedersoni
Size
To 2.5cm. 

Description
:
Transparent body with
purple spotting  on upper abdomen and claw arms. Walking legs transparent.and 2 pairs of long white antennae.

Ecology
Epibiotic, living among the tentacles of a sea anemone, usually  the Corkscrew Anenome (Bartholomea annulata), Knobby Anenome (Ragactis lucida) or Giant Anemome (Condylactis gigantea). 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.  This is by provoking the anenome to fire its nematocysts (stinging organs within the specialist cnidocyte cells in the tentacles), which have a chemical feedback systen causing it to stop stinging, so the shrimp builds up an olfactory aura preventing further "attacks".....the downside is that if it is separated from its host for a few days, it will need to repeat this procedure, since it will have lost this protection. 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.  Research has shown that fish recognise the Corkscrew Anenome (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.

Found at depths from 10 to 60ft (3-18m).
    Ecological Descriptors
Habitat Size (cm) Diet Behaviour Sex 
Co, R 2.5 Cle I, Sh
Epibiotic
F
Pederson Cleaning Shrimp
253
254
Pederson Cleaning Shrimp