Can anyone ID this worm like thing?

[BobbyZee]

I saw three or four of the small worm like creatures clinging to the glass of my tank when I was changing water. They are made me 5 mm long and were very difficult to photograph for whatever reasons. I have never seen this thing before in any of my tanks. I checked for detritus worms, but they were much thinner and longer than these guys. Too bad the picture came out so awful.

 

[Colin_T]

bit hard to tell from the picture but probably planaria

 

[BobbyZee]

Yeah, same thing I was thinking! Thanks, Colin!