Red Sea; Gulf of Aqaba; anemone; shrimp; fish; ecology; behavior; symbiosis

Several types of associations of shrimps and fishes with giant sea anemones occur in the Gulf of Aqaba: (1) Obligate mutualisms: Periclimenes brevicarpalis, P. ornatus, and Amphiprion bicinctus on anemones Entacmaea quadricolor, Heteractis crispa. Both the sea anemone hosts and the symbionts appear to profit, although occasional parasitism may present. (2) Regular facultative commensalisms: P. longicarpus, Kemponia tenuipes, and juveniles of Dascyllus trimaculatus associate several species of sea anemones that serve as shelters and ?fish cleaning stations? for large groups of P. longicarpus. (3) Occasional facultative commensalisms: The shrimps Stenopus hispidus and Urocaridella aff. antonbruuni rarely associate with sea anemones. Both shrimps are fish cleaners and may use the same crevices for shelter as do sea anemones and moray eels, or be fully free-living.