Are these starfish? Found 2 of them

[jackhoekstra]

 

[JumboShrimp]

Yes. An Asterina starfish.

Use the R2R "Search" feature and you will get many different opinions on them.

 

[exnisstech]

Asterina stars. There are a bunch of different types.

PS I had them for years with no issues but over the last year or two I've witnessed them eating zoas and the flesh off an acro so I treat them all as enemies now but I've found it very difficult to get rid of all of them. They just seem to appear outside of no where. There's speculation on which colored ones actual eat coral but I don't think there's been any study done on which ones are actual bad and which aren't.

 

[PPBlimpy]

yes, that is cool. Never seen ones with red coloring.

 

[CrewePD210]

A puffer will eat all of them quickly
\

 

[X-37B]

I have seen colored ones from time to time. I remove 10-20 a week from my 150. If you dont remove them you will soon have an asterina growout system. They multiply fast.
Harlequin shrimp will eat them all but then you need to remove it or feed it a chocolate chip star every couple weeks or it will not survive.

 

[DmitryB]

Found one yesterday in my bucket with live rock meant for a 170.

 

[JumboShrimp]

A pair of those thin metal tongs grab them nicely.

@X-37B , "Asterina growout system" ... ️

 

[fireorfrog]

Yeah seems like an asterina. Pretty good at cleaning algae, and can help reduce coralline on glass. But they also sometimes go rogue and start munching on corals, and once they start they don't stop. And they are prolific reproducers, so the best time to remove them manually is early. A lot of people like having them though, most of the time they're ok. Basically, get rid of them now, or take a chance for a pretty strong self-reproducing cleaning crew at some risk to your corals.

I generally try to make sure my cleaning crew is good enough regardless, and I don't want to deal with outbreaks. So the time I came across them in my tank I've gotten rid of them right away (no recurrence since). But if you do have a hostile asterina outbreak, you can get a harlequin shrimp to destroy them. Just keep that hunting echinoderms is what it does. It's all it does. A harlequin will terminate your asterinas, your other starfish (if you have any), possibly your sea urchins (if you have any), and then starve to death if you don't give it more starfish.

 

[jackhoekstra]

yes, that is cool. Never seen ones with red coloring.

It do look kind of cute doe

 

[EricR]

Whether or not some species eat healthy corals, I don't know, but enough people have experienced that to have some concern.

The reason I'd get rid of them is to avoid having an "asterina growout system" like mentioned in post# 6 <-- that's funny, I like that.

My LFS had a nice display setup right when you walk in.
*Red Sea setup not yet leaking, doh!
One day it looked awesome.
Next time I was there (maybe a month or two later?), the glass was practically covered with these asterina/aquilonastra/whatever stars.