small stars eating zoos

[wet reefer]

Has anyone had any experience with small stars about 3/8" eating zoos. Theses have shory stubby arms and range in color from blueish-gray to a cream color with some red-orange. The last few months I have had several colonies die off for no apparent reason. No signs of nudies anywhere. I usually see these starfish on the rocks but I have seen them directly on polyps. I dont have a camera to take pics. Could these be the problem?

 

[Zoalander]

are they asterina stars?

 

[wet reefer]

I have no idea. The only description I can give is that they are a 1/4" to 3/8" with very short stubby arms. I dont recall ever reading anything about zoo eating starfish but you never know. I was wondering if anybody had ever had starfish attack zoos before. I guess I am looking for a reason my zoos are declining. All water perameters seem to be fine.
55 gal loaded mixed tank with a 100 gal cheato ref/sump
(3) actinic white VHO
(1) actinic VHO
PH-8.1 ave
temp 81
phos-0 (at least not detectable)
nitrate-0
alk-2.5-3
cal-400 ave
very large diy skimmer
(2) 20 gal water changes per month

Same old story, zoos turn greenish-brown and disapear. Dips rarely help. Circulation is not a problem in this tank. I'm thinking of giving up on zoos and going with something easy like acros and other hard corals. The couple acros I have in this tank are growing like weeds. This tank was dominated by zoos-not any more. Everything else in the tank does fine. This seems to be a common problem with no easy answers.

 

[Pleco420]

I have those sons of you know what's in my tank...

I bought a pair of Harlequin shrimp, so I am trying to train them to go after the small ones. I do supplement with chocolate chip stars. Harlequin eat starfish exclusively...

 

[twon8]

I have noticed the same thing, but I tend to believe the stars are merely cleaning up a dead/dying zoo and not themselves the direct cause of the decline.

 

[wet reefer]

Did a search -guess I should have done that before. They are definately Asterina stars. It seems there are alot of differnet opinions on these. Some say they eat hard corals, some say they are harmless. I have seen them on polyps but I'ts hard to tell if it is eating a dead or dying zoo or caused the problem in first place. The tank has been set up for a year now and I never noticed these before. Now I have quite a few. To be safe I'll remove as many as I can although it will not be easy!

 

[CoralNutz]

I have lots of them. I have heard lots of mixed opinions on them as well. I have never noticed them eating anything but film algae...