Asterina star caught in the act!

Steven w · Feb 22, 2019

They definitely munch on zoas. Magicians shown here with star caught in the act. Removed it and zoa did make full recovery but took 2-3 weeks.

Saveafish · Feb 22, 2019

This might be hear say. But Ive been told several times if they are light grey or have orange specks they are safe. If they are dark grey or have greenish color they eat polyps.

JVU · Feb 22, 2019

I’ve heard the light grey good and dark grey bad association before several times too, which is why I asked to see the top side of this guy caught munching.

neoGeorge · Feb 22, 2019

andrewkw said:
100% they eat zoas and palys. I am trying to figure out if they will eat all or only certain kinds see https://www.reef2reef.com/threads/t...-my-zoas-and-palys.555362/page-2#post-5727580

In my in tank experience they certainly prefer certain types. I have 100 stars of various sizes in the container with different types of zoas and palys. I suspect it's only certain starfish but not necessarily certain species doing the eating as it's very difficult to ID different species. I have 1000s and 1000s of them in my main display and I am in the process of thinning them out. The sad thing is they do a good job of eating coraline and other algae, but for whatever reason they will turn to coral, either because there isn't enough food or they like it better.

I had one come in on a coral from Unique Corals; not knowing if it was bad/good/indifferent I called them and talked to their coral husbandry guy, who got real snarky with me (telling me that I will have to tear down the tank and start all over) - of course, he was exaggerating to make me feel bad about asking. So apparently they don't believe these little stars are an issue in a reef tank...

FishNerdVlogsYT · Feb 22, 2019

neoGeorge said:
I had one come in on a coral from Unique Corals; not knowing if it was bad/good/indifferent I called them and talked to their coral husbandry guy, who got real snarky with me (telling me that I will have to tear down the tank and start all over) - of course, he was exaggerating to make me feel bad about asking. So apparently they don't believe these little stars are an issue in a reef tank...

Haha he was just trying to cover his butt because he sent you a coral with a potential pest on it.[emoji23]

neoGeorge · Feb 22, 2019

FishNerdVlogsYT said:
Haha he was just trying to cover his butt because he sent you a coral with a potential pest on it.[emoji23]

You may have nailed that one, lol! I now have lots of these critters in the tank, for better or for worse!

Haggisman14 · Feb 22, 2019

I hate those buggers! I"ve caught too many munching on my zoa's as well. What started as "1" turned into waaaay too many! Got a Halrquin shrimp in my tank too!

shred5 · Feb 22, 2019

Rakie said:
The problem is there's a bunch of species of little stars, and they are given a blanket name -- "Asterina".

I have metric tons of asterina stars. They don't touch my corals. SPS, LPS, Softies, 100% safe.

Agreed anyone who say they all do has not idea what they are talking about.
do some species eat coral? yes. Do all, No..

andrewkw · Feb 22, 2019

shred5 said:
Agreed anyone who say they all do has not idea what they are talking about.
do some species eat coral? yes. Do all, No..

I think it has more to do with individual then species. I looked at a couple hundred and by looking at them, they all look to be the same species. Of course I have no way to do genetic testing so for all I know I have 10 different species here. If I had a macro lens I would have taken closer photos.

Another factor may be how much algae you have in your tank. If I don't clean my glass for a couple of days I get 100s if not more on my glass, but if I'm cleaning it there are only dozens. The (bare) bottom of my tank is always covered. When they are eating coraline on rocks sometimes they make there way over to polyps. I speculate a small fraction of them develop a taste for them either because there isn't enough food or they just like them better. Given that it's taken 100 in a confined space more then a week to consume a few polyps, if you have say 10 000 and some larger colonies you may not even notice the few they eat. Unless you only have a few small frags, growth in the colonies could be faster then whatever small amount they are eating.

shred5 · Feb 22, 2019

It is species and you can even tell by looking at some of them.
We had some that we used to pass around the reef club and about 15 of us had them and no one ever had a problem...
It may come down to individuals and other stuff too but there defiantly are species that never do and those that will almost always do..

I can pretty much tell the difference between a few that do and do not.

Ones that look like these always turn into issues.
http://www.garf.org/Star/starfish.html

andrewkw · Feb 22, 2019

shred5 said:
It is species and you can even tell by looking at some of them.
We had some that we used to pass around the reef club and about 15 of us had them and no one ever had a problem...
It may come down to individuals and other stuff too but there defiantly are species that never do and those that will almost always do..

I can pretty much tell the difference between a few that do and do not.

Ones that look like these always turn into issues.
http://www.garf.org/Star/starfish.html

Can you post a few photos of the top and bottom of the non coral eating ones you have.

I noticed on garf they say - Several people have argued that these starfish are harmless, but we have yet to find any that will not eat coral polyps.

I really don't think they are a plague that needs to be eliminated but they need to be controlled. I have removed a good 1000 from my tank over the last week and I'm going to keep thinning them out however I have no plans to tweezer every last one out yet.

shred5 · Feb 22, 2019

andrewkw said:
Can you post a few photos of the top and bottom of the non coral eating ones you have.

I noticed on garf they say - Several people have argued that these starfish are harmless, but we have yet to find any that will not eat coral polyps.

I really don't think they are a plague that needs to be eliminated but they need to be controlled. I have removed a good 1000 from my tank over the last week and I'm going to keep thinning them out however I have no plans to tweezer every last one out yet.

I do not have any in my system right now.

They disappeared many years ago.

Gonebad395 · Feb 22, 2019

I had them and caught a few eating zoas it was enough for me not to trust any of them bought a harlequin shrimp eradicated them and never looked back. I weighs it out like this 20,30,40,50 $ etc etc a frag bought because I liked to look at them. Starfish I didn’t want and do nothing for the esthetics of my tank easy decision stars gota GO!

littlebigreef · Feb 22, 2019

I'm going to be pragmatic here, do they all (every last one absolutely without a doubt) eat zoas. Maybe, maybe not, probably not. But, (everything before the 'but' was BS) I don't care to sit there and examine the colorations of each one individually. If the difference was more obvious (say like between a mojano and an aptasia) then sure. If you suspect that they're going after your zoas then you're just as well off eliminating them all and letting the 'god of starfish' sort them out. I've seen first hand the damage a large one, like the one @FishNerdVlogsYT found, can do in an evening. If you're comfortable with the idea of one of those crawling across your pink krak, *******, or gorilla nipples in the middle of the night then so be it.

JohnMzreef · Feb 22, 2019

littlebigreef said:
If you're comfortable with the idea of one of those crawling across your pink krak, *******, or gorilla nipples in the middle of the night then so be it.

ehehehehe, eheheheh

DSC reef · Feb 23, 2019

shred5 said:
Agreed anyone who say they all do has not idea what they are talking about.
do some species eat coral? yes. Do all, No..

I don't think anyone is saying they all do. I've said multiple times in ID threads that it's impossible to know which are bad so I recommend removing them to be safe. Plenty of people know what they are talking about as they have plenty of first hand experience. FWIW, seen colored and light ones eating our zoas so all were removed because a proper ID is too difficult