Critter ID help please

[Just John]

I can't get a photo - it's too fast. Maybe you can help me narrow it down. It's some kind of worm. Only about 1/4" right now. When the lights go on it moves very rapidly into the sand from the rock and moves like a centipede. So, it definitely has legs. Wondering if this is probably a fire worm and if it is what will eat it. It's only a 10 gal tank, so it needs to be just 1 fish or critter. Thanks!

 

[Eagle_Steve]

I can't get a photo - it's too fast. Maybe you can help me narrow it down. It's some kind of worm. Only about 1/4" right now. When the lights go on it moves very rapidly into the sand from the rock and moves like a centipede. So, it definitely has legs. Wondering if this is probably a fire worm and if it is what will eat it. It's only a 10 gal tank, so I needs to be just 1 fish or critter. Thanks!

Google bristleworm and compare images. That would be a good place to start.

 

[Just John]

Google bristleworm and compare images. That would be a good place to start.

That's the first thing I tried, but it's very difficult to tell because it's so small and as soon as I turn on the light it disappears in an instant. Perhaps a better question is what worms have legs, move very rapidly, and in an S shape like a centipede or snake. Maybe a lot of worms move that way or maybe just a few. I really have no idea.