What is this?

[whasamada]

I just noticed this thing on the glass a few days ago. Its very small, kind of looks like a starfish. This is an established tank, maybe a year old. I dont know where it could have come from. I do have sandsifting star I purchased a long time ago and a few months back noticed baby brittle stars which I assume were hitch hikers on a coral or frag but that's the only ones I noticed. Ideas?

 

[keagan]

Asterina starfish they can be a nuisance

 

[whasamada]

Asterina starfish they can be a nuisance

Should I pull it out?

 

[keagan]

Should I pull it out?

I would personally and any others you spot, however some people just leave them be. It's debated how much damage they do but I've seen them eating zoa's before.

 

[Fish Fan]

Here's a few posts from ISpeakForTheSeas on these guys:
https://www.reef2reef.com/threads/mystery-star.1162489/post-14413469https://www.reef2reef.com/threads/is-this-an-asterina.1159045/post-14361736https://www.reef2reef.com/threads/h...tarfish-to-their-tanks.1152497/#post-14251798
Good luck!

 

[whasamada]

I would personally and any others you spot, however some people just leave them be. It's debated how much damage they do but I've seen them eating zoa's before.

Thank you for the advice! I removed it just to be safe

 

[Randy Holmes-Farley Verified Community Expert]

I personally leave almost anything that is naturally in the tank. I’ve seen these rise and fall in populations in my old tank and never tried to remove any. They never were any issue.

 

[keagan]

I personally leave almost anything that is naturally in the tank. I’ve seen these rise and fall in populations in my old tank and never tried to remove any. They never were any issue.

In my old tank I had one species that was harmless and fed on biofilm/algae that came with my live rock early on. I eventually wound up with a different species that came off a frag that immediately started chowing down on my zoa's. I don't disagree with your ideology though I'm sure the corallivore species are rare in our aquariums or wed hear more people cursing about asterina

 

[Fish Fan]

In my old tank I had one species that was harmless and fed on biofilm/algae that came with my live rock early on. I eventually wound up with a different species that came off a frag that immediately started chowing down on my zoa's. I don't disagree with your ideology though I'm sure the corallivore species are rare in our aquariums or wed hear more people cursing about asterina

People definitely report having the variety that munches on Zoas. For that reason, I kind of think if it's crawling up the glass, leave it be, it's likely feeding on biofilm. If it's anywhere near any Zoas, I'd be much more suspicious. I have personally never had the Zoa eating variety, the ones I've had have been fine as far as I could tell. Some claim that the shade or color of the star can be an indicator as to whether or not it eats Zoas, but I would personally lean more towards observing its behavior.

 

[keagan]

People definitely report having the variety that munches on Zoas. For that reason, I kind of think if it's crawling up the glass, leave it be, it's likely feeding on biofilm. If it's anywhere near any Zoas, I'd be much more suspicious. I have personally never had the Zoa eating variety, the ones I've had have been fine as far as I could tell. Some claim that the shade or color of the star can be an indicator as to whether or not it eats Zoas, but I would personally lean more towards observing its behavior.

IMO, after that experience, I don't take any risks there's enough CUC in most aquariums without risking it but that's personal preference. My concern with asterina is some could be opportunistic carnivores that decide to eat a coral after wandering near it.

 

[EnterName]

I personally leave almost anything that is naturally in the tank. I’ve seen these rise and fall in populations in my old tank and never tried to remove any. They never were any issue.

Did you keep Zoas in your old tank?

I frequently saw them munching on zoa polyps in my tank. It's not too bad if you have a bunch, but if they snack a new expensive frag with a single polyp it's pretty annoying.

I tried to find out if I can differentiate the bad and the good ones, but I haven't been able to find a visual clue that identifies them with certainty. It's already hard enough to tell if they are actually Asterina or Aquilonastra.

 

[keagan]

Did you keep Zoas in your old tank?

I frequently saw them munching on zoa polyps in my tank. It's not too bad if you have a bunch, but if they snack a new expensive frag with a single polyp it's pretty annoying.

I tried to find out if I can differentiate the bad and the good ones, but I haven't been able to find a visual clue that identifies them with certainty. It's already hard enough to tell if they are actually Asterina or Aquilonastra.

The only really reliable way to tell them apart is with a microscope but I wouldn't even know what to look for.

 

[Randy Holmes-Farley Verified Community Expert]

Did you keep Zoas in your old tank?

I frequently saw them munching on zoa polyps in my tank. It's not too bad if you have a bunch, but if they snack a new expensive frag with a single polyp it's pretty annoying.

I tried to find out if I can differentiate the bad and the good ones, but I haven't been able to find a visual clue that identifies them with certainty. It's already hard enough to tell if they are actually Asterina or Aquilonastra.

I only had zooanthids at one point. They were not any sort of highlight. Back then most were not that attractive and mine did not thrive, though the asterina were not apparently on them. I don’t know if I even ever had them simultaneously.

The asterina seemed mostly on the glass.

 

[EnterName]

Did you keep Zoas in your old tank?

I frequently saw them munching on zoa polyps in my tank. It's not too bad if you have a bunch, but if they snack a new expensive frag with a single polyp it's pretty annoying.

I tried to find out if I can differentiate the bad and the good ones, but I haven't been able to find a visual clue that identifies them with certainty. It's already hard enough to tell if they are actually Asterina or Aquilonastra.

The only really reliable way to tell them apart is with a microscope but I wouldn't even know what to look for.

Yes, I've read about that during my research, but I have to upgrade my scope with a second light source to support reflected light microscopy.

Right now I'm limited to transmitted light. You can push enough light through to see something, but it's still not the same.

 

[EnterName]

Did you keep Zoas in your old tank?

I frequently saw them munching on zoa polyps in my tank. It's not too bad if you have a bunch, but if they snack a new expensive frag with a single polyp it's pretty annoying.

I tried to find out if I can differentiate the bad and the good ones, but I haven't been able to find a visual clue that identifies them with certainty. It's already hard enough to tell if they are actually Asterina or Aquilonastra.

I only had zooanthids at one point. They were not any sort of highlight. Back then most were not that attractive and mine did not thrive, though the asterina were not apparently on them. I don’t know if I even ever had them simultaneously.

The asterina seemed mostly on the glass.

Hmm, I see. Not all seem to eat Zoas and it's not their main food source, so you might not have noticed or simply gotten lucky.

If you decide to go for zoas again in the future, I can recommend borrowing a Harlekin shrimp for some time though

 

[Randy Holmes-Farley Verified Community Expert]

Hmm, I see. Not all seem to eat Zoas and it's not their main food source, so you might not have noticed or simply gotten lucky.

If you decide to go for zoas again in the future, I can recommend borrowing a Harlekin shrimp for some time though

That was my old tank and the new one seems to not have any asterina. :)

 

[EnterName]

Hmm, I see. Not all seem to eat Zoas and it's not their main food source, so you might not have noticed or simply gotten lucky.

If you decide to go for zoas again in the future, I can recommend borrowing a Harlekin shrimp for some time though

That was my old tank and the new one seems to not have any asterina. :)

Well if that isn't a reason to get some Zoas I don't know what is

I think a small "zoa garden" would fit nicely into your tank