Id ?

[SeattleDarko]

it doesn't look like the pics i have found of the bad flat worm I never see it do anything but clean rocks...

 

[ccCapt]

Looks like a stomatella.
The Grazing Snails, Part I - Turbo, Trochus, Astraea, and Kin by Ronald L. Shimek, Ph.D. - Reefkeeping.com

 

[yote]

+1 Capt

 

[SeattleDarko]

I seem to have a lot of these in my fuge too, I was down there poking around and found a lot.

 

[yote]

They'll breed like guppies,so its not surprising to have a bunch of em.

 

[dcantucson]

Can they be harmful?

 

[winyfrog]

stometellas are good. :)