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FAQs about Limpet Snails, Acmaeidae, Fissurellidae and more, Scutus, Stomatella

Related Articles: GastropodsSea SlugsMollusksAbalone

Related FAQs: Limpets 1, Limpets 2, Limpets 3, Limpets 4, & Limpet Identification 1, Limpet ID 2, Limpet Behavior, Limpet Compatibility, Limpet Selection, Limpet Systems, Limpet Feeding, Limpet Disease, & Marine Snails 1Marine Snails 2Marine Snails 3, Marine Snails 4, Snail ID 1, Snail ID 2, Snail Behavior, Snail Selection, Snail Compatibility, Snail Systems, Snail Feeding, Snail Disease, Snail Reproduction, MollusksSea SlugsAbalone

Keyhole Limpets and Other Snails, repro., comp. -- 3/10/11
Hi Crew,
<Hello Sam, Lynn here today.>
I have a 24 gallon Aquapod. Among my critters is a pair of Keyhole limpets that I bought about 2 years ago. I now have a few dozen babies and am curious as to how they manage to reproduce.
<It varies, but typically they broadcast gametes (sperm and eggs) into the water column. Interestingly enough, some actually brood their young.>
I seem to find the babies in the most unlikely places like in my hang on skimmer.
<Yep, I can tell you from personal experience that they also like hang-on filters! Judging from the fact that these limpets reproduce successfully in home aquaria, they more than likely have a very short free-swimming larval stage. Many likely perish during this period due to equipment issues and predation. However, the lucky ones find sanctuary in the relative safe haven of skimmers, filters, fuges, and the like. There, they find an environment with sufficient food to entice them to settle and metamorphose into tiny replicas of their parents.>
They grow very slowly.
<Yes, they do -- or at least mine seemed to.>
My first set of babies are still about half the size of a split pea. Aside from the fact that they are very difficult to remove as compared to the average snail
<Heee! Hence the term 'clings like a limpet'!>
..they seem to be good algae eaters. For some reason one of the adults does bother one Blastomussa wellsi that I have.
<Funny you should mention that. I had the same experience with one of the limpets I had. I caught it munching on my favorite B. wellsi one morning and promptly banished it to the fuge!>
It almost destroyed it 3 times already but each time it recovered.
<That's the great thing about Blastomussa wellsi, in good conditions even a polyp that's been reduced to a near speck can regenerate itself.>
I now keep the Blasto on my crushed coral figuring the limpet will not like to pass over that and since then it has not harmed it.
<Good thinking>
I also have a few Strombus snails, the kind that lay these little round see thru packets of eggs.
<Are they the snails typically referred to as 'Strombus Grazers'? If so, they're more than likely Columbellids, aka 'Dove Snails'. They're wonderful little grazers that reproduce like rabbits. Please see the following link for more information and photos for comparison: http://bb.wetwebmedia.com/viewtopic.php?f=25&t=341 >
I used to have 6 adults but now have 2 plus 3 small ones. I still see many egg packets but it seems that very few make it.
<Something may be preying on them or perhaps there's just not enough food to go around.>
These things seem to go in cycles. I used to have hundreds of Stomatella snails and now am down to a few here and there.
<Don't you just love these little snails? Sadly, other critters love to pick at, and eat them, particularly peppermint shrimps.>
Just sharing,
<Thank you for your terrific observations!>
<Take care, Lynn Z> 

Stomatella Spawning Constantly in Nano! Help! 4/9/10
<Hello Megan, Lynn here today!>
I have come across very little negative info about Stomatella...the closest thing I saw to a caveat was on WWM...someone with a larger tank than mine was assured that Stomatella spawn (unlike coral or clam spawn) is pretty harmless in a larger tank (I think the guy had a 75 gallon) and that this is not normally a problem, "except maybe in a Nano..."...but the crew member did not elaborate...
<Yep, usually they're a welcome addition and not a problem.>
Well, I have a Nano....12gal.
<Uh-oh, NASA we have a problem.>
We started with one tiny Stomatella from the LR, then did not understand why our water was cloudy for a few weeks.
<That's an awful long time to stay cloudy. Did you try checking your parameters and running carbon?>
Then we saw new snails. Now, we have seen them spawning with our own eyes, and so realize why water had tiny particles, back then & now.
Back then we only had the one adult snail, water cleared up fast.
But now we have 10-15 adults and they have been spawning every single day for past 3 weeks!
Doing water changes actually triggers spawning even more!
I do like these snails but wonder if this is good for my tank...the fish eat the eggs, but the Crocea clam I have produces a lot of mucus to get the eggs off of him.
<I bet. If the clam's getting irritated, then it's not good.>
The water quality is still good...nitrate has not gone up excessively, no ammonia, etc.
We have persisted with weekly water changes anyways because I don't want to have a dirty AND eggy tank.
<No kidding>
I realize we don't know what makes them spawn...so I just need to know if this is bad and what we can do to control the snails (if not their spawning).
<I would control their numbers. Remove and perhaps sell or give some/most away to fellow hobbyists (try a local fish club).>
I have very peaceful fish that do not eat snails and am not too interested to get a hunter type of fish but will consider any advice!!
<That would be my next recommendation, but only if you want to get rid of them all. Peppermint shrimp (Lysmata wurdemanni) reportedly prey on Stomatella snails, along with some crabs and hermits. Unfortunately, all of those can be pickers of other things as well and cause problems. Personally, I would opt for reducing the population and running carbon or something like Pura Filtration pads to help clear the water.>
Thank you as always for help with this extremely specific question.
<You're very welcome and good luck!>
<Take care, LynnZ>

Re: Stomatella Spawning Constantly in Nano! Help! 4/12/10
<Hi Megan>
Thanks so much for the detailed reply!
<You're very welcome!>
We had a peppermint before. He kept the Aiptasia under control (ate them any time they started to grow)
..but I hated his picking
<Yep, that can really be annoying.>
...and anyways he died, natural causes I think (he molted 3 times in one month and the last time he died). We did get another small peppermint last week because the Aiptasia have slowly started to come back
<Aiptasia can multiply quickly in systems with excess nutrients, so do try to keep them as low as possible. Hopefully, reducing the Stomatella numbers will help with this. Please see the following links for more information regarding:
Nutrient control: http://www.wetwebmedia.com/nutrientcontrol.htm
Aiptasia control: http://www.wetwebmedia.com/marine/inverts/cnidaria/anthozoa/aiptasia/aiptasia.htm >
...did not know he would eat snails also
<Oh yes. Stomatellids, since they can't retract all the way under their shell, are vulnerable to a lot of critters. In a tank without predators, you'll often see them out and about during the day; otherwise, they're mostly nocturnal. The problem is that Pep's seem to do most of their picking and eating at night so the poor Stomatellids never get a break.>
...but he picks too, and is picking at my little colony of brittle stars
...and so his days may be numbered in our little reef.
<I don't blame you.>
We changed the carbon bag to polish up the water and Stomatella seemed to have stopped for a few days at least. I agree that manual removal is probably best idea...once we get over the yuck factor.
<I'd use something like an algae scraper to remove them from the glass and catch them with a net or turkey baster. If the snails are on the rockwork, you might just try nudging then suctioning off with a turkey baster.>
They are very soft, and the shell is like paper...plus they move really fast!
<Heeee! Yes, it's surprising how quickly those little guys can move, considering they're snails! They'll also drop the hind portion of their foot, just like a lizard drops part of its tail, when threatened by a predator. The detached section squiggles and squirms, hopefully distracting the enemy long enough to allow the snail to make a quick getaway. I just thought you should know about this in case it happens during collection. The snail isn't actually dividing into two, it's just trying to get away!>
Thanks as always WWM.
<It was my pleasure, Megan.>
This is a wonderful service to amateur reefkeepers everywhere.
<Thank you! Bob has indeed compiled quite a stockpile of information, hasn't he!>
<Take care, Lynn Z>

Incredible Mr. Limpet Multiplying 7/13/09
Hello all.
I would like to start by saying you have a great site. I've found most of my answers to my seemingly endless dumb questions here.
And on with the show... A little background info, my sister had a ten gal. tank for about 1 year. In this tank she had a fuzzy dwarf lion,
<Mmm, crowded...>
a few blue legs, button polyps, mushrooms, live rock, and ONE quarter sized limpet. She gave the tank to me roughly 10 months ago. About 2 months ago the limpet died from an unknown cause.
<"Variable water quality" likely>
About 3 weeks ago I noticed 15 tiny (1/8 inch) limpets roaming around.
Nothing has been added to the tank in the last 14 months. So here is the questions. Can limpets reproduce asexually?
<Mmm, not as far as I'm aware. They release eggs or sperm into the water column, cued environmentally...>
Have they been in there the whole time unnoticed?
All of my research says they reproduce sexually (w/eggs and sperm) around stormy times of the year, but I only had ONE. Since I first noticed them 3 have almost doubled in size, so I have a hard time believing they've always been there unnoticed.
Thanks in advance,
Derek from Holiday, Florida
<Thank you for sharing Derek. Bob Fenner>

Stomatella varia, sel./source   04/02/09
I've spent a hours searching the web for a place to purchase Stomatella Varia. So far I've come up with very little and nothing reliable. I've spoken to people at my LFS's and they are keeping an eye out for me as
they do their water changes. However, in my searching I've found numerous others on many forums stating that they wish they could find a place to buy these.
So my question is 2 fold:
1) Are there places online where these snails can be purchased online w/o buying a whole 'refugium kit'?
<Yes, please see here:
2) Why are they so hard to find?
<Good question! They are definitely some of my faves.>
The only suggestion on how to get them that I've seen is "buy live rock..you'll likely get some". But with so many looking in vain I can't help but wonder why no one seems to sell them.
<Do please contact Morgan L. of Inland Aquatics. I have bought these snails from him many times and they always arrived healthy.
Sara M.>

Question about limpets HI Robert, I found your article on Mollusks: An overview on the internet and decided you would know the answer to my questions. We watched two limpets in a display last night in our tank that we think might have been their reproduction process but we are unsure. Both key hole limpets were on the glass, the smaller one ( 1 1/4 in long) was releasing from the key hole an almost clear liquid that would disperse into the tank. It looked almost like smoke. The other, larger one ( 1.5 in long) was higher up on the glass and the release from this limpet was whiter, thicker and dispersed slower. They did this back and forth for at least 30 minutes that we were aware of. Were we watching the release of eggs and sperm? <Likely so> If so, how long will it be before we will see tiny limpets in the tanks? Is this common? If not, what were we watching? <... probably won't see limpet young... the products here will probably be collected by your filtration... removed by skimming... pelagic larval stages have tough times in captive systems. Bob Fenner> Please email your answers to XXXX. Thanks! Carol Griffith 

Hitchhiker Snail Reproduction: Stomatella varia - 1/17/08 Hello WWM, <Hi there!> Thanks for all you do. <It's a pleasure, indeed!> I have a hitchhiker snail that I saw trying to reproduce in my tank. I tried to get some pictures but they were hard to take with the xenia in the way. <Understandable - can be tough to get good photos of such small subjects - especially considering water flow/movement.> What are the chances something like this can reproduce in my system? I've only seen one of these in my tank. <What you've got is a Stomatella sp., likely Stomatella varia. They're harmless/beneficial little herbivores/grazers, highly variable in color, reproduce readily in our tanks, and can get up to ~1.25' in length. With such a small shell and so much exposed foot, you'd think that this species would be very vulnerable to predation. After all, how can it possibly protect itself if it can't retract into a shell? Well, nature has allowed for this. Stomatellids are mostly nocturnal, can move *very* rapidly, and have the ability to detach the hind portion of their "foot" (the 'metapodium'). This is similar to some lizards detaching a portion of their tail when threatened. The sacrificed segment wriggles and writhes, thus distracting the predator and supplying it with a tasty tidbit -- allowing the snail to escape. Potential predators of Stomatellids include the usual 'pickers' - hermits, shrimps, and crabs. Some fish also find them tasty, but the snails' mostly nocturnal nature helps to eliminate them from the menu. Sometimes confused with sea slugs, Stomatellids are actually in the family Trochidae, which includes the more familiar/recognizable Trochus spp. (Trochus/Top Snails), Margarites spp. (Margarita Snails), and Norrisia sp (Moon Snails). Regarding reproduction, unfortunately, if you have only the one female in your tank, the eggs she released were not fertilized and are therefore not viable. They will simply become part of the food chain. Hopefully, there are some small, not yet mature candidates around for future spawning events. As far as method, Stomatella spp. are broadcast spawners. The male releases sperm into the water while the female releases her eggs. In most cases, this means that the young have very little chance of survival in our tanks. However, such is not the case with Stomatellids. What tips the scale in their favor is the fact that the young have a very short pelagic larval stage, during which they don't need to eat. After several days of drifting about in the current, they settle to the rock/substrate as miniature versions of their parents, and begin to graze. All in all, they're fascinating little creatures and make terrific additions to a reef tank!> Thanks, <You're very welcome! Take care. -Lynn>

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