White Starfish invasion

I need some help, my tank is getting invaded by these long thin legged white starfish. I would describe it as a white Brittle starfish.

Here's the thing, this morning on 1 rock alone, I counted at least 10, when the lights first came on.

Right now the largest is no bigger then the head of a screw, but I don't think I want this many.

Any thoughts as to what they are, and how I could get rid of them?

Is it a astrea starfish?

Sounds like micro brittles. Google those and see if that is what you have. They are scavengers and are a benefit to the tank. They won't get any bigger than what you are describing.

If it isn't that look up hydroid jellyfish.

Seems like Micro Brittle is the answer.

And apparently they are a good thing, next to too many being esthitically unpleasing

Most of them will run and hide when the lights are on. They're an excellent hitchhiker to have.

I must have 1000 of these things in my tank. No idea where they came from. I haven't added anything to my take in a long time, then that was a fish, not something they could hitch hike on. Still, I don't find them unappealing. They hide in the light. Its funny to watch them at feeding time. Little arms poking out of the corals and rocks. They are even in the sump. Found several in my skimmer last time I took it out for cleaning.

There is a website called LionfishLairs.com. They have pics of most bad critters and good critters in your aquarium.