What is this thing? ID help please?

[tnc112105]

I attached a picture to help with the identification of what looks like a baby sea slug or worm of some kind.

I'm not quite sure where it came from, but there seem to be 7 of them so far. They stay stuck to the glass for the most part, but they can also swim. This is the first time I've noticed them in the tank. They move around, the round end appears to be the head (considering the direction they're moving) and the pointy end is the tail.

Can someone help me id these please? I don't know if they are good or bad for my tank.

Thanks!
Christy

 

[franklypre]

looks like a flatworm of some sort

 

[LeslieH]

Yup, a flatworm, what's commonly called an Amphiscolops although that may not be accurate. It eats tiny crustaceans & worms, micro-algae, etc. Think of it as a glass-cleaner.