Is this the dreaded Aitapsia?

[Brian1956]

Half a dozen of these have turned up in my 6 month old marine tank. They are 1/4" to 1/2" long. Are they what I think they are? (apologies for poor picture quality).

 

[SNAKEMANVET]

That looks like a spaghetti worm.Harmless,are a good for cleaning up the sand bed.

 

[Woogiekids]

Nope, not aptasia