Hitchhiker StarFish question

[ameno]

Don't remeber the name of them but the small starfish that usually have five legs, a lot of times a leg or two is missing. I have had these in my tank for years, and always thought they were reef safe and a good thing to have, but at a LFS this weekend they were collecting some in a bag and claimed that they eat Acros. Never heard of that, is it true? should I be getting rid of them? since I've starting keeping sps corals.
Also I found another type of starfish, it has four legs and is about the size of a quarter, it looks like a bigger version of the small 5 leg ones, does anybody know what kind these are and if therre reef safe?
Thanks

 

[mx#28]

I bet you're thinking of the Asterina genus stars.

 

[ameno]

not sure the proper name, but that could be it

 

[ameno]

bump

 

[scopus tang]

Another site associated with "Geothermal" has pictures of the sps eating stars - I've also got some small (pencil eraser size) five-legged ones that I've introduced to several of my tanks. I don't believe they're the same, but you might want to check out the pictures and see if what you have is the same.

 

[ophiura]

They are all Asterina stars and though QUITE rare there are some problematic species. But even seastar experts can not easily identify them so I question the id on that site. In fact I sent it to a seastar expert once and he was pretty incredulous when he read their stuff.
So keep an eye on them. There are many species and they are impossible to ID by color, size or number of arms. They are what is called polymorphic - meaning it has many forms if you will. They will not become predatory. They WILL eat dead or dying corals however. They may have found a predatory species, they may have dying corals...or they may be responding to nothing but the hype promoted by that site (and if that site does have predatory Asterina in their systems I would certainly avoid anything from them!).
The majority of hobbyists probably have these stars, and EXCEEDINGLY few have the SPS predator. More will have some that eat and kill calcareous algae, which is actually an adaptive strategy on the part of the algae.

 

[ameno]

Thanks Ophiura, I was hoping you would come in and help shed some light on this.
The store I was at had recently relocated and some of there corals looked pretty bad, so that could be were they were coming up with this, or maybe as you said, some hype they had heard. I know I have had these for years and never had a problem but haven't dealt with sps so I wanted to be sure. glad there ok because there would be know way to get rid of all that's in the tank.

 

[scopus tang]

Originally Posted by ophiura
http:///forum/post/2477970
They are all Asterina stars and though QUITE rare there are some problematic species. But even seastar experts can not easily identify them so I question the id on that site. In fact I sent it to a seastar expert once and he was pretty incredulous when he read their stuff.
So keep an eye on them. There are many species and they are impossible to ID by color, size or number of arms. They are what is called polymorphic - meaning it has many forms if you will. They will not become predatory. They WILL eat dead or dying corals however. They may have found a predatory species, they may have dying corals...or they may be responding to nothing but the hype promoted by that site (and if that site does have predatory Asterina in their systems I would certainly avoid anything from them!).
The majority of hobbyists probably have these stars, and EXCEEDINGLY few have the SPS predator. More will have some that eat and kill calcareous algae, which is actually an adaptive strategy on the part of the algae.
Yeah, thanks for the info - takes a load off my mind since I just introduced about 20 each (that came from someone elses tank where they've never been a problem) into two different systems, because they eat hair algae.