Need help identifying this critter

[Savo]

New to the hobby, no idea what this is. Looks like some kind of starfish. Found two of them and they love hanging out with the coral

 

[KJ]

Asterina starfish watch them.

 

[Crabs McJones]

Asterina starfish watch them.

+1, they can multiply quickly.

 

[hwntunda]

^+1! One week I had less than 10 by the end of the month I just kept netting them off my glass constantly

 

[Savo]

The chaeto I got from my lfs was definitely not clean. Came with a bunch of new life some good some bad

 

[Florida Sunshine]

+1 on Asterina star. I've never had trouble with them but others have reported issues particularly with zoas.

 

[Kmack0415]

+1 harliquin shrimp will take care of them quick, once they are gone trade it in or buy a chocolate chip starfish for it to feed.

 

[Ewelina]

+1 on Asterina. I keep removing them and putting in a sump. Someone said that they munched even on the coral glue, making the frag fall off the rock.