dead blue linkia

okay, in my 55gal I have only two fish.  Volitan lion and a yellow tang.  I have a sea cucumber, little red starfish, anenome (long tenticled?  purple, and big) and a flame scallop.

I also had a blue linkia starfish, and it went immediately for the underside of the rocks at the top of a little cave.  yesterday, I noticed that he fell off the top.... and I began to worry because the end of one of his arms was kind of eaten.  so I took him out.  his top side (which was pointing down, because he hung on a ceiling) was all kinds of torn up, with some hanging out guts and everything. 

My lion likes to hang out in this cave, so I was wondering if his spikey back was tearing up the star, or if this is a sign that I have a baddie in  my tank that I cannot see?  thanks for any help.

Yep - if he looks to be eaten away it is most likely that he is starting to deteriorate. It isnt necessarily someone picking or eating him, it is just that he is wasting away. Those blue linkias can be difficult.

Connie's experience is amazing to me.  I have never seen a sea star bounce back once they start to fragment.  The only sea stars that have lasted more than a year for me are the serpent stars and the sand sifting stars.

Most of them just start to spontaniously crumble, and don't stop until they become a pile of sea star dust.