Blue translucent sea squirt

Scientific name : Rhopalaea sp.

Elegant solitary ascidian, cylindrical, small (3-5 cm). Colour can change, but it is usually a blue tone: from transparent sky to an opaque darker blue.
Often on books the species Rhopalaea crassa is found. Waiting for a systematic revision, we prefer to use the name Rhopalaea sp.. No one, from the species that we photographed, correspond exactly to R. crassa description.
This opaque blue form, probably another species, is easily found in bay or lagoon.
Rhopalaea spp. are common on back reef, reef front but mainly along the external reef. We have often observed clusters of individuals, not having any connections among them (not colonial).
Small commensal amphipods can be found inside the ascidian. On the external surface the commensal goby Pleurosicya mossambica can be seen.
Rhopalaea spp. are preyed upon by some nudibranches, e.g. Nembrotha spp.
Ascidia sp. 2, in the blue form, is larger, more rounded, always found on the underside of rocks and corals, while Rhopalaea is found in positions more exposed to current.

Associated organisms
Small commensal amphipods can be found inside the ascidian. On the external surface the commensal goby Pleurosicya mossambica can be seen.
Rhopalaea spp. are preyed upon by some nudibranches, e.g. Nembrotha spp.