Does anyone know what this is?

[asylumdown]

Or you could do what I did... Wait util their population is measured in the millions, until there's so many it looks like you've got a novel species of red coralline algae covering every square inch of your rock, don't siphon them at all, THEN treat with flatworm exit.

They form a mucous that holds mats of them together as they die, so as they start to lift off the rocks they come off in great sheets that look like underwater fire. For 30 minutes it will look like the sacking of Rome in there. Coolest thing ever.

Ay LPS that ate the dying worms were toast. About a third of my corals were seriously damaged or bit it completely.

On Second thought. Don't do what I did.