Acropora Eating starfish

[ryansreef]

I noticed that one of my new acropora frags was turning white around the base. After some inspection and lots of searches on the internet I came to the conclusion that it was these small starfish that were eating the flesh off of my new coral! I was able to catch one (hopefully there aren't any more). here is the pic

and the underside

 

[jrgilles]

I have many hundreds that look like that in my tank. They just seem to eat algae though. I've seen em on some big Zoas once, but I think they were just cleaning...

Maybe the kind you have is different than what is in my tank

 

[NWDiver]

It looks like an astrina star, I don't think they typically eat coral. Would one of you kind admin/Mods move this to the invert board so Leslie can weigh in?

 

[Faciosity]

Those are asterina stars, and they mostly just eat algae. I am convinced that I've caught them eating zoanthids, but I highly doubt that it would eat SPS corals. Probably a coincidence that it happened to be there. Often when a coral is having issues, many scavengers will apear to eat the dead/dying tissue. It is possible that he was getting an easy snack from something that is having other reasons for recession.

 

[Chichas01]

hmmm sounds like a case of starfish profiling to me :lol:

 

[ryansreef]

I took it in to Kevin at Aquatic Dreams to help identify it and we compared to the safe algae eaters that he has in his tank...definitely not the same species. I also compared to the starfish listed at the GARF website and many others have had the same issue with these eating their SPS. Check it out here: GARF predatory starfish 11/25/01
The pictures are not very good so it is hard to tell the detail but they were definitely eating the acro.

 

[Herefishyfishy]

I actually add these into my system from other peoples tanks.

GARF has always given astarina stars a bad rap and even after 100s of reefers have coexisted with them for over a decade, they never updated nor said oops.
99% of the time (if not more) that I see astarina stars get blamed for eating a coral, soon after the underlying problem in that display surfaces.
Could be chem warfare, mini-cycle, old bulbs or coral too low in the display, etc etc.


No doubt it was munching on the dying acro tissue, the question is what turned healthy polyps into something that smelled like detritus...

 

[jrgilles]

I took it in to Kevin at Aquatic Dreams to help identify it and we compared to the safe algae eaters that he has in his tank...definitely not the same species. I also compared to the starfish listed at the GARF website and many others have had the same issue with these eating their SPS. Check it out here: GARF predatory starfish 11/25/01
The pictures are not very good so it is hard to tell the detail but they were definitely eating the acro.

I'll leave this one to Leslie then Look similar to what is in mine, but ID on these guys can be very tough. If you did a side by side comparison, then you are off to a good start. Hope there aren't too many more in there.

If there are, maybe they eat acro's only? And you can use that to catch/remove them from the tank...

 

[NWDiver]

Interesting, most of the tanks I know have little guys that look very much like your picture. Mine are pretty much all white.
Looking forward to Leslie's comments.

-Todd

 

[returnofsid]

I agree 100% with Mike!

GARF gave these guys a bad rap, which I think was undeserved. I've read literally hundreds of threads, about this same issue. Almost every thread, where Asterinas are attributed to bothering corals, the GARF thread is brought up...lol.

I have thousands of Asterina starfish in all 3 of our tanks, and have had them in all of my past tanks. I've never seen them bother anything at all.

There are many species of Asterina starfish and there's some indication that there may be 1 or 2 species, that 'may' bother corals. However, once again, most of this 'evidence' originated with GARF.

I believe that Asterinas have been seen, seeming to eat corals. However, in every case, I also believe that the Asterinas were actually finding a easy meal, in an already stressed coral, by eating dead or dying flesh.

 

[LeslieH]

Hi all --
I really think we need to stop using the name Asterina. As of a couple of years ago there were 26 genera in the family Asterinidae. I tried to identify some specimens & got hopelessly lost due to the complexity of the characters used to separate the genera (which could be saying more about my non-polychaete ID skills than anything else!). Anyway, they are very difficult to separate even at the generic level. The small, asexually reproducing species are spread among several genera so maybe it's best to just say "asterinid", which means a member of the family. Food preferences aren't know for most species. For those that have been studied, preferences vary from herbivore to predator to scavenger to grazer to sifter depending on the species and I bet they will switch foods if starving.

The only way to know for sure that a particular star is a coral predator is to put it in a container with a healthy coral and see what it does. Otherwise there are several different scenarios. The top two, already mentioned above, are: The coral is sick/damaged due to other reasons and the star is scavenging necrotic tissue OR the star - especially if there's a ton of them - may not have enough food so they're going for whatever is available.

Once upon a time I read through a couple years' worth of asterinid posts, trying to find some kind of clues as to which ones were peaceful reef citizens & which were predators. In general, the small white ones were sediment & micro-film grazers while the predators tended to be larger & more colorful. Not always, but generally. I found the GARF posts a little single minded as they seemed to say that all small, asterinids belonged to a single species & were predators which just isn't true.

But just to be on the safe side, Ryan, since your star is colored and you did find it on a coral, maybe you should start removing them. Donate them to someone who has harlequins to feed.

There was one very interesting post - can't remember who wrote it or where, sorry - about a possible correlation between asterinids & zoa-eating nudis. The poster never had nudis but did have lots of asterinids. At some point he decided to remove the stars. Once he did the nudis started showing up & devastating his zoas. There were no other changes in his tank that could explain it so he stopped removing the stars & the nudis disappeared again. One post doesn't prove a relationship but it would be really intriguing if other people noticed the same thing.

 

[kevinpo]

Hello,
As mentioned by Leslie this is a very diverse group of sea stars. The Acropora eating ones are quite rare in the hobby. I have only seen one other besides Ryan's and that was 10 years ago. Most of the small white ones with light brown/tan markings commonly found in our tanks are film type algae eaters. The one Ryan brought in has a blue colored spot on the top center visible under magnification. It also has more tissue between the legs.

Regards,
Kevin

 

[treehugger]

I've noticed that the populations of these types of starfish often correlate to your nitrate levels. Like most say they do tend to seem to just consume algae/diatom. They do however enjoy congregating on a dying/damaged coral. So the real question is...are they really the problem or just coincidentally present when there are other issues at hand.

 

[Playapixie]

Ok, then. So I have a new tank which was set up with live rock and sand from two long-established tanks. Many teeny things hitched in and are thriving so far. Today I noticed the first of these itty bitty starfish (I think that's what it is). It's really, really tiny and white. Hanging out on the glass.

So, do I let it stay? Or evict him now while he's one and not hundreds?

Thanks...!
Dawn

 

[Herefishyfishy]

Dawn, all depends on how much you value hitchhikers and diversity. If you prefer lots of different stuf, keep em. If you aren't sure, toss em.

 

[Aquanaut]

Hey all, in our hobby we encounter many unusual or curious creatures which we have under our care. We must all try to respect these living animals for what they have found a nitch in this life. I highly recommend that before considering the mutilation and destruction of any species to consider placing these on the free classifides to re-home to someone who just may apreciate and collect these and other items. "One man's trash is another's treasure" Everything is given a purpose, no matter how insegnificant that may seem.