What kind of snails are these?

[russells55]

They seam to be reproducing because I see tiny ones

been going on for months in my nano 13.5 gal fluval. I have counted 20 of them once.

and now is starting in my main 65gal (likey because I used sand from the nano)

cheers thanks

 

[FishTruck]

LUCKY! I think those are nassarius snails. Do they burrow in the sand?

 

[russells55]

Yes!
They are always under the sand and then when I put food in. Especially like brine or mystic shrimp they come out of the sand like a horror movie and are pretty fast for a snail

 

[IKD]

Nassarius snails. Like to burrow in the sand. Good snails to turn the sandbed over.

 

[FishTruck]

Seriously, that is really a treasure. Don't get hermit crabs.

 

[Spare time]

They're the best scavengers for leftover food other than brittle and serpent stars

 

[Tcook]

Mystic shrimp? Didn't Julia Roberts star in that?

 

[addictedtoreefing]

Another hitchhiker on coral. Is it astrea or? has red parts on top. does it eat coral? Have had astrea before but thislooks a little different. Groeing fast too. About an inch now.

 

[ISpeakForTheSeas]

Another hitchhiker on coral. Is it astrea or? has red parts on top. does it eat coral? Have had astrea before but thislooks a little different. Groeing fast too. About an inch now.

Yeah, that's an "Asterina" star (technically Aquilonastra as I mention below). Some of the species can get pretty big.

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.

 

[russells55]

Ah do hermit crabs eat these snails?

what about coral banded shrimp?

 

[FishTruck]

Ah do hermit crabs eat these snails?

what about coral banded shrimp?

Yes. If you get hermit crabs, one day you will notice that your nice nassarius snails are walking funny and not burrowing. That will be because they have been evicted from their shells and what you are now looking at is hermit crabs. I have a snails OR hermit crab policy at this point.

 

[addictedtoreefing]

Another hitchhiker on coral. Is it astrea or? has red parts on top. does it eat coral? Have had astrea before but thislooks a little different. Groeing fast too. About an inch now.

Yeah, that's an "Asterina" star (technically Aquilonastra as I mention below). Some of the species can get pretty big.

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:

thank you. its kind of pretty. guess i will leave in quarantine tank for now.