What is at the bottom of pic? Orangish threads coming up through the sand, underneath a substantial ganglia. Notice this several times now when doing water changes. It is friend or foe?
Looks like a spaghetti worm. Usually they are pretty harmless but there are many species of them so I couldn't say it's 100% reef safe but most usually are harmless.
Agree, spaghetti worm. Often see a little pile of sand over the tentacles. I've never had them cause a problem.
