Litter Red Critters, please ID

[psott]

I've had these around for months with no visible ill effects but am finally able to get a better shot of it with a new lens I got for Christmas.

They are little red slug like things maybe 2mm by 6mm that are occasionally on the glass if I don't clean it for a few days but mostly on the coralline algae on rocks.

Any ideas as to what I have>?

 

[Max H.]

Looks like a red planaria flatworm

 

[psott]

Thanks for the quick reply, looking around online I think you are right.