unexpected arrival - hitchhikers

[danimal]

My friend arrived tonigt with a polyp rock from another friends 700 gal tank. The piece is in excellent condition, but this is coming from 10 year old system that is vibrant.

There are two small white star fish and what appear to be to 50 to 100 small brittle stars ( size of a dime. reddish center body , red and yellow bands on the legs, 6 legs) crawlin all over the rock. Many hav three short legs and 3 long legs opposite each other - others that are a little bigger have legs that are close to the same length.

What chance do I have that these little brittles will be bad for my tank?
They would be impossible to get off the rock.

 

[smpoylp]

I have seen odd legged starfish as I call it. They look white with a dirty brown. I had one(and family) eat an Acro of mine. Some years ago I've gotten them again. I'm not sure what they are eating but they are surviving. A harliquin shrimp from what I've heard is the trick. I'm just letting mother nature work till I see something wrong(like eat a $ coral).

 

[tangir1]

Almost all those Astrae (?) starfish are harmless, and very common as LR hitchhikers. I have thousands of them in my tanks, FWIW.

 

[elpescado]

The two small white starfish are most likely Asterina sp. Lots of debate over whether or not they eat corals. I have seen hundreds of them over the years and have yet to see one actually on top of a coral leaving any kind of damage path behind it.
Those serpent/brittle stars are detrivores meaning they scavange on decaying materials and sediments in the tank. I have yet to see any of them actually attack a heathy coral.
But if they do cause you any problems be sure to let people know. Photos would be helpfull. Sharing info is how everyone learns.