Anemone? Coral? ...it glows green and purple...but doesn't need light...

So... I have this thing growing on the underside of a rock shelf. It has a hard white skeleton and clear tubes that come out of the skeleton. It seems to be open day and night and glows a crazy bright green with purple tips under blue LEDs. I have included a photo (it's not mine), but it's exactly what it looks like. It seems to be doing great, but can't be getting any light where it's located. What are these things in the picture? Any thoughts on what I've described might be?

 

Phyllangia americana

Hidden Cup Coral Nice HH score!

 

Thanks! - That looks to be it!

Ok... now how do I take care of this guy... or do I let it be? Should I flip the shelf over? When I say shelf - it's live rock (supposedly from Sri Lanka) and it's covered in coraline on the top, so I'm pretty sure he originally grew on the bottom... these rare?

 

They usually don't do well in aquariums.

But it does prefer shade and if it's extending I'd say it's happy where it is and to leave it there.

Everytime I've seen a cup coral it's always been a hitchhiker from the Atlantic.

 

You will need to feed it or it will die.