Questions regarding possible worms?

[FatCow]

Last night when the lights were out with the moonlight on, I noticed floating wiggling worms like creatures all over the tank.
I shinned flashlight at them, they looked like tiny worms that wiggle around, extending into a string and retracts into a ball.
Does anyone know what it may be? Is this some sort of parasitic worm infestation? So far the fish are fine.

thanks in advance.

 

[mustang2021]

it maybe an invert probably shrimp larva

 

[FatCow]

Thanks for the reply.
I checked it again last night at lights out but did not see them. They were extending up to 1 inch in length when I saw them the other night. Hopefully it's not anything bad.