Starfish ID'd. A threat?

[Oldsalt01]

For the past week I've seen two of these things wandering around an old Trochus shell a friend gave me to jump start my corraline. I've only seen them on the shell itself and they live inside it, and are apparently feeding on the corraline. I've ID'd them as Asterina Starfish, by color and shape, but the problem is I'm getting both "KILL 'EM and "LEAVE 'EM ALONE" recommendations in my research as to whether they are a threat to my proposed Zoa garden. As my tank is new (4 weeks), I don't want to start out with a problem which will manifest itself further down the road. Nothing else in the tank (14g BioCube) right now as I'm taking this one slowly and waiting for my QT to cycle. Recommendations please. (Sorry for the lousy pic, but the darn things just won't smile for me.)

 

[The Kahnasaur]

They are eating the corraline. That is why they haven't left the shell. They may or may not eat your Zoas. They ate many of mine. They breed very quickly. I removed them from my pico tank and it's finally growing corraline after several years. I have dozens of them in my main tank and therefore only grow corraline on the equipment. I've also found that they can eat unhealthy/dying LPS tissue.

 

[thehammer1985]

The probability of you getting the species that eats zoa is very slim. I'm not saying it can't happen but there are many different species of asterina. Im not gonna tell you what to do but me personally I'd leave em and watch em . They are detritus eaters and great biodiversity for the tank.

 

[stephen_g]

I've got two different kinds of asterina stars in my tank, some like yours and some that are a dark brown/orange color. The brown/orange stars are the ones I usually see on my corals and try to get off. The lighter ones like yours seem to just eat the algae and detritus as thehammer said

 

[Oldsalt01]

So far, it seems "watch and wait" is the main concensus (2:1). Guess I can do that. I'm all about biodiversity and i have waited 15 years to have a reef tank again so....