Could be either one. Their appearance changes based on water and diet. But the two species (genus?) do act differently in the way they feed and react to danger.
That's what I'm thinking too. I can see the crawdads digging through the gravel looking for them. So either way the crawdads or fish will get them in the end.
So I was looking at the tubifex worms and the california black worm, and it's the black worm for sure. I found some pictures of them up close and they look the same. Now I just have to figure out how they got in there.
I you guys want some more information on the black worms that I found in my tank look at this thread I found. There's alot of good info here and it seems like it's a good thing that I have them in my tank. //www.aquariacentral.com/forums/showthread.php?t=214961