Is this a starfish?

[psness]

I saw this on my tank glass a few weeks ago and thought it is a baby brittle starfish, although I've never had one in my tank and haven't added anything new in months. Then today I saw three at the same time. They are white and no more than 1/4 to 1/2 inch from tip to tip. Their movement sure looks like a brittle star. Any thoughts on what they are and how they got into the tank?

 

[lbcathee]

I have a bunch of those that live in my chaeto too. They don't get any bigger. I think they just help to keep things clean. At least mine haven't bothered anything. :)

 

[BL1]

They are micro brittle stars and a good member of your cuc

 

[Homer]

I saw this on my tank glass a few weeks ago and thought it is a baby brittle starfish, although I've never had one in my tank and haven't added anything new in months. Then today I saw three at the same time. They are white and no more than 1/4 to 1/2 inch from tip to tip. Their movement sure looks like a brittle star. Any thoughts on what they are and how they got into the tank?

Nope, that`s a start shaped fish, that also is called porcupine ... :