Brittle Star question

I got a frag from the LFS and after putting it in a noticed a tiny start come out of the rock and go right into one of my big rocks. Was too fast for me to catch it or take a pic. It was light colored with reddish rings on its arms. Do I have anything to worry about? I know there isnt much info to go on but.....

 

Most likely a micro-brittle star, which is a harmless detritivore/scavenger. At the worst, it may be a juvie serpent star which might require periodic target feedings to curb any opportunistic tendencies once it matures, but will also be easy enough to remove at that point as they get fairly large. Until then, still a harmless scavenger.

 

Yup, Like Bill said its probably just a harmless addition to your clean up crew.

 

Thanks for the help guys. I got a harlequin shrimp a couple weeks ago to keep my astrea stars in line so they 2 may meet up at some point. lol

 

That can be a problem, and the reason I don't recommend a predator to eliminate a pest--

For starters, the asterina stars are harmless detritivores, scavengers, and algae grazers, and their population is controlled by the amount of available food. There is a type that preys on zoas, but unless you've seen them on zoas and found damage to the polyps, you only have the good guys.

Furthermore, harlequin shrimp do not eat sea stars, they only feed on their soft tube feet; with only asterina stars available, they've been known to attack LPS corals for sustenance and survival. The chocolate chip star is the most popular choice among aquarists with harlequins, but they prey on clams and soft corals...

FWIW, the coral reef is not a peaceful haven for all of it's inhabitants, it's a violent ecosystem where everyone eats their neighbors, so just because your LFS carries a particular critter doesn't mean it's safe for your tank.