[chadly]

doesnt' look like a planaria to me. The fish in the pic who is looking at the worm is a sparkling gourami for size comparison. It's probably close to 1/2 - 5/8 inch long. It kinda just sat there for a while, then when I came back to check on it, it was gone.

 

[chadly]

never had a visible problem with them. They sit on the glass and don't move much. I still have them with no ill affects.