I see all these small brown worms in my snapper's tank. They are attached to the the heater, gravel, floating logs and the shells of my snappers... theres ALOT of these worms. They don't move, they look like they are dead and pressed against all the surface. They are not flat like leeches, they are round in appearance but very small.

What type of worm are these exactly and where do they come from?

How do you eradicate the situation? I tried cleaning out the entire tank bleaching the whole thing... that was 6 months ago and now all the worms are back. I think they are coming from the snapper's poop.

thanks for any advice you can offer me.