stingy leather

[Surferlopez]

anyone know what this is, it seems to be some kind of filter feeding organism. it seems like it has bore a hole into one of my finger leather and a green sinularia i have. whenever it catches some kind of particle it retracts. has anyone seen these before?
Danny

 

[EdKruzel]

That is a common Ctenaphore. They are harmless and do not bore into the corals.
They are very similar to a flat worm with very long extensions for capturing particles of food in the water column.
They are most active at night and will reach a near plague proportion if you feed heavily (especially phytoplanton).

Enjoy them while you can as they seem to breed themselves out in captivity.

Ed