A translucent blue vase standing from shaded rock, up to about 8 cm (3 in) tall, with two openings at the top - a larger one that draws water in and a smaller that sends it out. The body wall is clear enough that the internal basket shows through, which is what makes this species worth a close photograph.
A sea squirt is a far closer relative of a fish than of anything else on the reef. Its larva is a tadpole with a notochord, a nerve cord and a tail, and it swims until it finds a surface, cements itself head-down and then digests most of its own brain, since a sessile animal has little use for one. What remains is a pump: water in through the big siphon, food strained out on a mucus net, water out through the small one. The blue colour comes from pigment in the tunic rather than from anything living inside, unlike the corals surrounding it.
- translucent blue vase-shaped body with two openings
- grows singly or in small clusters, not as a sheet
- internal structures visible through the tunic
- height up to 8 cm
