Starfish ID

[RWhitt907]

Found him on my glass right before lights out. What is this?

 

[RWhitt907]

Found him on my glass right before lights out. What is this?

 

[ISpeakForTheSeas]

As accurately as you can say, how big is the star?

Any chance of a straight-on pic of the top under white light? (The pic you've got isn't bad, but this could potentially get a somewhat clearer, more color-accurate pic).

That said, my best guess at this point is some Aquilonastra ("Asterina") species.

 

[Dburr1014]

Asterina, harmless. You will probably get hundreds.

 

[Pistondog]

Asterina.
How big is your Tank?
If you let them multiply to dozens or hundred, they will sustain a harlequin shrimp for 6 months. A cool shrimp. When 1st introduced to a tank, they rub their claws, must release some thing, which causes all the asterinas to climb the glass.
That shrimp only eats starfish, so youd have to rehome. I gave mine to a friend who watched the 'starfish whisperer' in action.

 

[RWhitt907]

As accurately as you can say, how big is the star?

Any chance of a straight-on pic of the top under white light? (The pic you've got isn't bad, but this could potentially get a somewhat clearer, more color-accurate pic).

That said, my best guess at this point is some Aquilonastra ("Asterina") species.

About the size of a quarter

 

[RWhitt907]

Asterina, harmless. You will probably get hundreds.

Don't they eat coral?

 

[RWhitt907]

Asterina.
How big is your Tank?
If you let them multiply to dozens or hundred, they will sustain a harlequin shrimp for 6 months. A cool shrimp. When 1st introduced to a tank, they rub their claws, must release some thing, which causes all the asterinas to climb the glass.
That shrimp only eats starfish, so youd have to rehome. I gave mine to a friend who watched the 'starfish whisperer' in action.

I've got a 75 display. I want them so I can get a harlequin but don't they eat coral?

 

[Pistondog]

I've got a 75 display. I want them so I can get a harlequin but don't they eat coral?

Asterinas eat coraline, never had any bothrr coral, but some species might.

 

[Dburr1014]

Don't they eat coral?

There have been reports that red looking ones may* have bothered coral. I think those are rare reports.

 

[kjkszpj9]

There have been reports that red looking ones may* have bothered coral. I think those are rare reports.

the ones in my 13g tank are very blue and tiny never seen them eat any of my zoanthids, no zoas have died even.

 

[ISpeakForTheSeas]

I've got a 75 display. I want them so I can get a harlequin but don't they eat coral?

There have been mixed reports about if they eat corals or not, but they seem to generally be safe (zoas seem to be the main corals suspected of being eaten):

Personally, I like them, but they do tend to reproduce very quickly.

I've heard some species eat corals and others don't - I've seen convincing evidence for one species (a very darkly colored one), and one piece of somewhat convincing evidence for one different species, but the vast majority of these guys seem to be at least mostly safe.

With regards to whether or not the average "Asterina" (technically Aquilonastra - Asterina is a separate genus within the Asterinidae family) eat corals, it might be a species specific thing, it might be a you have way too many starfish so they're out of other food options thing, it might be they're eating the slime coat/mucus on the coral rather than the coral itself (see below), or they might just opportunistically eat unhealthy corals. Based on how starfish eat, it seems plausible to me that it may also be coincidental (i.e. the star goes to eat something off the coral and the coral just happens to be one that is able to be negatively effected by the star's everted stomach). Regardless, Zoas are just about the only coral I've heard about regular "Asterina" stars potentially going after with any sort of frequency.

A quote I like to refer to for this:

Timfish said:
It's an Aquilonastra spp. starfish and is a great scavenger. I see them with anywhere from 4 to 12 legs. The whole discusion around them seems to me excellent examples of misidentification, mistaken behaviour and assumed causality based just on heresay without looking at the research. Asterina spp starfish are preditary but only reproduce sexually and are shortlived so while it's possible some might get into a tank even if it did happen it's not going to be around long. Aquilonastra are one of the uncommon species that reproduce fissiparous or by splitting so are easy to identify by the different sized legs regrown after splitting. They perform an important function not only feeding off algae films but also feeding off microbial films including those on corals (at least ones that don't sting). FYI the mucus coating on corals ages and corals have to periodicely shed it to renew it and maintian healthy microbial processes (Ref 1, Ref 2). If Aquilonastra are feeding on zoas or softies I'll argue they are either benign or even beneficial as they may be reducing the unhealthy older mucus which can be full of unhealthy microbes which the animal is trying to get rid of and are far more likely to be the actual problem.

Here's an example, this Toadstool is doing one of it's periodic sheddings. The Aquilonastra have been in this system for years but only climb onto the Toadstool when it's shedding. In the first picture you can see the old mucus film, Aquilonastra starfish and areas they have cleaned off. The second picture shows the Toadstool a week later.

With regards to Harlequins and Aquilonastra stars, it's a short-term arrangement:

Close on the spelling - Aquilonastra.

Both Aquilonastra and Asterina are genuses of small starfish in the Asterinidae family, but Asterina stars are typically predatory and (at least primarily) reproduce sexually while Aquilonastra stars are typically not predatory and tend to reproduce more through asexual means (they’re fissiparous, so they reproduce through fission - basically they either split in half or drop a leg, and then the splits halves or the main body and the dropped leg then regenerate into fully-formed individual starfish). The fissiparous reproduction is why their populations tend to reach extreme levels in our aquariums; they can reproduce sexually as well (though I’ve never heard of them spawning in our tanks - it might happen unseen), but because they spawn rather than laying eggs or birthing live young, the spawn would likely be wiped out in a normal reef tank (pelagic larvae tend not to do very well in our tanks due to predation, removal by equipment and water changes, lack of available proper foods, etc.).

I would guess that a healthy Aquilonastra star with proper food and water quality would survive a surgery like this and regrow into two stars, but I question if it would be more effective than allowing them to do naturally reproduce. I would guess that allowing them to do it on their own would be less stressful and likely result in higher rates if reproduction, but I could be wrong.

Either way, though, while there’s a fair chance that harlequins could spawn with an Aquilonastra diet (I haven’t been able to fully confirm this yet, and it may depend on the Aquilonastra species fed to them, but there is some evidence to suggest that it would work), you would need to consistently produce an unreasonably large number of stars to feed the harlequin broodstock and offspring long-term - these guys clean out even 300 gallon reef tank Aquilonastra infestations in weeks, not years.

So, to put it another way, short of basically beginning a commercial Aquilonastra farm with several hundreds of gallons of highly functional culture tank space and constant optimization of Aquilonastra culturing methods, you won’t be able to produce enough stars to feed even just the two shrimp in the broodstock pair of your farm as each shrimp will probably eat ~10-30 (accounting for different species and their sizes) Aquilonastra stars a day when full grown (see the quote below). So, assuming you need ~20 a day per full-grown adult shrimp, you’d need to be able to produce ~14,600 stars a year just to feed two adult shrimp.

about 15 a day,controlled feeding, she's only sm-med rt now

TLDR; It’s theoretically possible to farm harlequin shrimp using Aquilonastra stars as feeders, but it would require culturing an obscenely large number of stars to maintain a very small number of harlequins, so I would recommend against it.