ID these starfish?

[tmarshall14]

These three starfish just appeared yesterday- have never seen any in the tank and now to find three? Haven't added in any rock or coral in many months so I am not sure where they came from. I was thinking they were Asterinea, but don't quite look like the pictures I've seen.
Any ideas?

[Ashlar]

Asterina sp. 99 out of 100 will be harmless algae grazers.

[Twizted1]

Asterina sp. 99 out of 100 will be harmless algae grazers.

The man know his stuff. +1

[delta1190]

they are so cool my son said he saw one in our tank i said no then one day me and my wife both saw it wow !!!

[Ashlar]

If you see one, there are likely more that you're not seeing.

Once you get the 'knack' for spotting them, suddenly you'll see a bunch.

[discus513]

If you see one, there are likely more that you're not seeing.

Once you get the 'knack' for spotting them, suddenly you'll see a bunch.

Isnt that the truth they go from being cute to being a pita, like Ashlar said most of them are harmless, there are a few species that can eat zoas though, there are also some of them that can repopulate very quickly and will pretty much be all over your glass. I normally just pick them out every now and then and dry them out, at one time I had thousands of them but I got a harlequin shrimp and he pretty much ate all of them!

[chromiumlux]

A Sixline wrasse will keep them under control.

[volcano]

Since my harlequin vanished, their population has exploded in my tank.  The ones in my tank reproduce extremely fast.  Fortunately, they don't eat my zoas, but I still hate them.  I have just gotten in the habit of plucking everyone I see with tweezers and drying them out.  Problem is that I could probably spend hours removing them and still not dent their population.  Maybe I should invest in another harlequin and a 6 line wrasse.