What is this worm?

[KatNor21]

Found this worm near the substrate in my shrimp tank. It's long and slender, brown, and glides along surfaces/water surface. I injured it when grabbing with tweezers to remove; that's why the middle is almost severed. It reminds me of planaria but bigger and slimmer and without the arrowhead. When you zoom in, it has speckles. No clue what this is or if it can harm my shrimp.

 

[Colin_T]

Just an aquatic worm, possibly tubifex. They are harmless and normally live in the substrate.