Need help identifying

[bdrogers2000]

I bought some live rock a few months ago, and within a few days I started to see what I think are starfish on the back of my aquarium. All of them are rather small, and none have all of their arms. I am pretty surprised they survived the transport from the LFS to my house because the rock was not submerged in water.

I asked the LFS staff what they think these might be, and the consensus is Blue Linkias. My main concern is that whatever they turn out to be are relatively reef safe, this is a FOWLR but I have a carpet anemone that my clownfish are rather attached to. I am also a little worried about the size of the organisms once they are full grown. I have a 240 gallon aquarium, but I have counted at least 16 of them. Until recently they were exclusively on the back wall so it was hard to see many at one time.







The first two photos show them on the rock. Some are defiantly a bright blue like I would expect out of a Linkia, but most are more of a dull blue. The third photo shows one on the front glass so the underside is visible (also an action photo of my Sailfin Tang chasing the juvenile Queen Angelfish). I apologize for the photo quality, all I had was my cell phone.

[FoMoCo Master Tech]

Looks to me like a type of asterina anomala. I have tons of them but none are blue. Mostly whiteish grey. Mine are harmless algea grazers but some can be coral predators. I doubt they are linckias but I could be wrong.

[FoMoCo Master Tech]

If they hang out on the glass or rocks and away from corals and such, I would assume they are grazing on algea or bacterial film and such. They will reproduce or split like crazy.

[Original Fin]

The off white ones look like asterinas to me too, and I also have dozens of them harmlessly grazing the rock. The blue ones are seem to be the same size and shape, so maybe another strain of asterina, not sure.

[bdrogers2000]

Thanks everyone!

I have a FOWLR tank, so I'm not worried about them eating coral. I was mainly concerned that they might turn on my carpet anemone, but that doesn't seem to be an issue.

At this point I will let them be. I had a bit of an algae problem, and it looks like they are helping get that under control. My porcupine puffer tends to eat the larger snails over time so these guys are probably taking the snails place in the cleanup crew. I saw the puffer try to eat one off the glass a few days ago as well, so anything that will keep his teeth ground down is a good addition as far as I am concerned.