Evidence of (some) "asterina" / aquilonastra stars eating (some) zoanthids

[ISpeakForTheSeas]

DNA relying on location for species identification may not be so reliable. (Here's one example.)

Yeah, I tend to view using location as a way to narrow the list of possible species, or, in some cases, a shortcut showing the most likely species with some probability of error (how large the probability depends on the species involved). It's definitely not ideal (or even necessarily reliable) to rely on location alone for an ID in most cases.

 

[taricha]

looking more into ID'ing these to the species level, I can see why (it took a bit of work to piece together what parts of the stars I needed to look at and where to find them on the specimens)

Same here. The key is a steep learning curve of what anatomy to look for, where to look and, how it distinguishes. None of which is obvious.

I'll get you some better pics of the spineless on the top side.

 

[Timfish]

Have you given any thought to duplicating this experiment with the same zoas and aquilonastra at 3, 6, 9 and 12 months? Doing so might show if there's a stress response or an acclimation process involved.

 

[taricha]

Have you given any thought to duplicating this experiment with the same zoas and aquilonastra at 3, 6, 9 and 12 months? Doing so might show if there's a stress response or an acclimation process involved.

The biggest difficulty for me would be keeping a mostly stable aquilonastra population over months. In my system they multiply quite well, and H
one harlequin shrimp bring their population to essentially zero. So the data I have the simplest way to collect is vast hordes of stars, versus essentially zero. I'm open to ideas about how to keep a stable modest Aquilonastra population.

 

[Timfish]

When they get too numerous (obstructing the view) I'll wipe them out with paper towel or siphon them off with a steel straw

 

[taricha]

To address this aspect in Part 2 - I have a harlequin shrimp that has now removed all visible stars from my system. We'll see how the zoa frags do with the aquilonastra stars essentially wiped out from the system.

Here's part 2.
Without the aquilonastra stars present, none of the types of zoanthids I have show decrease in polyp counts.

The "Red" is the same frag as in part 1.
The "orange" is a replacement zoa frag that looks like the Orange I had in part 1.
The "P+B+Gn" is rock shared by purple, blue, and green zoas. I give the total polyp count because some colors naturally crowded out others.

Again, I'm not comparing zero stars to modest amount to huge population. The only comparison here is between zero aquilonastra and huge population. There may well be some population level where the stars are more beneficial than harmful. I'm only comparing extremes. in my system, the extreme that the zoas do better with is zero stars rather than hundreds.
The zoa frags have been in the same spot on the sand where zoas did poorly with a large star population.
No other tank inhabitants (urchins, crabs etc) have been changed.

 

[twentyleagues]

Here's part 2.
Without the aquilonastra stars present, none of the types of zoanthids I have show decrease in polyp counts.

The "Red" is the same frag as in part 1.
The "orange" is a replacement zoa frag that looks like the Orange I had in part 1.
The "P+B+Gn" is rock shared by purple, blue, and green zoas. I give the total polyp count because some colors naturally crowded out others.

Again, I'm not comparing zero stars to modest amount to huge population. The only comparison here is between zero aquilonastra and huge population. There may well be some population level where the stars are more beneficial than harmful. I'm only comparing extremes. in my system, the extreme that the zoas do better with is zero stars rather than hundreds.
The zoa frags have been in the same spot on the sand where zoas did poorly with a large star population.
No other tank inhabitants (urchins, crabs etc) have been changed.

I am a firm believer that "asterina" stars are zoa predators. I watched it happen in my tank years ago. Healthy zoa colonies with stars I'd pull off them and there would be a hole where the star was. Harlequin shrimp fixed my issues also.

 

[Patx]

I had "a few asteria" visible to the eye on the rocks, for say 1 year...
the population is growing and is starting to appear on the walls here and there.
They were part of my cuc... no problem, I think they were doing a good job.
until I saw one park 1-2-3 days "on a bambam polyp" until I decided to put my hands in the water to remove it and confirm what was happening underneath... yep, i found a polyp in flesh.

ok enough for me, everything is proven, no need for a 2nd opinion.
My tank is mostly zoa/paly....

I salute your research and identification efforts.

for me it's clear no matter what they look like, I don't need/want them. no gray area at my place...
if you are not reef safe.... out and that's it.

I'll send you pictures, the next time I go fishing for them.

 

[VintageReefer]

Nobody will ever convince me they are not zoa predators.

 

[taricha]

aside, I don't actually stick to the rigid rule - "no coral grazers/totally reef safe only".
my longspine urchin occasionally lightly munches the tip of a hard coral, but he eats so much algae that he gets a pass.

But I've never had a hard coral decline due to the longspine urchin. My zoas did decline with 100s of aquilonastra stars. And yes after the star removal, the film algae around my tank really took off. Surfaces that were "clean" became fuzzy. The system is still finding the balance after removal of 100s of film grazers.

 

[taricha]

for me it's clear no matter what they look like, I don't need/want them. no gray area at my place...
if you are not reef safe.... out and that's it.

I'll send you pictures, the next time I go fishing for them.

I would be interested in the pictures of yours that you find are zoanthid munchers.

And more generally, I'd love to have pics of tiny stars that people feel are well-behaved around zoas. At this point I feel it would be extremely useful to have candidates for "good guys".

 

[VintageReefer]

I would be interested in the pictures of yours that you find are zoanthid munchers.

And more generally, I'd love to have pics of tiny stars that people feel are well-behaved around zoas. At this point I feel it would be extremely useful to have candidates for "good guys".

This is what I think many people don’t understand. There are multiple type of these stars and they all look very similar

If you are a person who says they don’t eat zoa - that’s in your experience with the ones you’ve acquired. There are varieties out there that eat zoa and some people unfortunately get them

 

[Troylee]

I would be interested in the pictures of yours that you find are zoanthid munchers.

And more generally, I'd love to have pics of tiny stars that people feel are well-behaved around zoas. At this point I feel it would be extremely useful to have candidates for "good guys".

I can’t help with Zoa eating ones cause I don’t have Zoas.. I have around 10 tan ones tgat are the size of a quarter and bother nothing, and a few hundred little tiny 1/8” ones that are grey and stay on the bottom of my glass where I don’t clean that often..

 

[Patx]

just to confirm,
they only spawn by fragment?
if i transfer them to another tank connected to the system. (Just for observation)
any chance they can get through a filter sock?

I would be curious to see if they "change spot/color pattern" when they don't have any zoa to nibble on.

 

[Patx]

It's been 3 days in a row that I've removed an Asterina that parks on a Bambam (never the same polyp).

 

[taricha]

just to confirm,
they only spawn by fragment?
if i transfer them to another tank connected to the system. (Just for observation)
any chance they can get through a filter sock?

The type I've had only do fragmentation. A few stars in the sump took years before any made it through the return and become visible in the display.
Over or around the sock maybe, but not through.

I would be curious to see if they "change spot/color pattern" when they don't have any zoa to nibble on.

Ones from my sump with no corals had identical coloration to those from the main display. So I don't think this happens.