HELPPPP What could this be

[ren00ryu]

My carnation and colt corals died off suddenly over a 3 week period(i uess not suddenly). They first turned white and kept shrinking until they just became mush. My pumping Xenia too died and I have a colony of button polyps that too have closed and started shrinking as well.
I noticed that my live rock is starting to look greenish, gray/brown and my and has lil bits of particles that are the same color on it as well.

I started seeing a strange looking worm thing on the rocks, it looks kinda like a mini starfish arm, you know the real tiny starfish that you get in those refugium booster/starter packs. Only thing is they are starfish arms, they move like a snake forward and backward and they zip across the rock very quickly. They look black and white(banded look pattern) some are all white and they are about 1/16th of an inch long. I wondering if anyone know what they could be and if they are parasitic and how can i get rid of them.
I couldn't get a picture that was clear enough to show them.

 

[black_majik]

Not parasitic.

 

[Sabre38]

Im guessing that the nutrient level in your tank is low, carnations dont need as much light as most of your corals and need to continuosly be fed. Im guessing youve got a skimmer as do almost every reefkeeper nowadays. These two items IMO (thats the 1st time ive ever used that) dont mix. The xenia could be slightly affected by this as well but the colt im not so sure of.

As pretty as carnations are they have completely different husbandry requirements then most of the other corals most of us keep. As for your little aquatic critter, im pretty sure Ive seen what your talking about. I doubt its them.

 

[snorvich]

First of all, this is the wrong forum for this question. You will get much more help in a different forum. In any case, questions like that should always be accompanied by water parameters.