I have seen this pink sponge identified as Dysidea arenaria. It is usually seen in quiet lagoon waters, usually attached to rocks but sometimes growing as a separate colony on sand. It is also seen commonly on lagoon bottom shipwrecks at depths exceeding 30m.
A matching Goniobranchus nudibranch can sometimes be found on clumps of this sponge.
Created 1 June 2019
Updated 27 April 2021