These tiny acoel flatworms live in groups on living corals and other invertebrates. There may be more than one species among the photos. They are common on Plerogyra sinuosa (bubble coral) and Heterofungia.
On a faviid coral with the brown and white banded aceol Amphiscolops sp. The brown flatworms with white rings could be different from the Waminoa above.
On a crown-of-thorns starfish, Acanthaster planci.
Created 29 January 2021