Thorny stem sponge

Appearance

Spiky tubular sponge. Its forms a neat small bush (about 20cm) with closely packed narrow tubes (about 1-2cm wide) regularly ringed with large neat spikes, forming a star-like shape around the large hole at the tip of the tube. There is a transparent 'lip' around the hole which is more obvious in a submerged sponge. Colour lilac to bluish.
These sponges come in a range of sizes from minuscule encrusting species under rocks to massive sponges which can be up to one and half metres high.
They are able to filter many liters of sea water every few seconds.
Their colour can vary if growing in the light or when growing in the shade

Distribution

Widespread Indo-West Pacific.

Habitat

Found between corals and rocks over coral and rocky reefs. Depth - 0-100m.

Reproduction

They feed on plankton.

Defense

Sponges can exude highly toxic chemicals and so have very few predators apart from nudibranchs, sea stars, sea urchins and umbrella shell.