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Carnivorous Ramshorn Snails ?


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#1 gerald

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Posted 31 January 2015 - 05:17 PM

NOTE:  This thread was split off from another thread: http://forum.nanfa.o...rate-questions/

 

BEEKER wrote:

I must recommend AGAINST ramshorns.  They will eat healthy, as well as rotting, plants.  Actually, they will eat anything, even eachother.  They are fierce and will multiply like crazy.  I bought 5 Assassin Snails to take care of an overrun 30 gallon tank, and I've found that the ramshorns have killed and eaten some of my Assassin Snails.  I know I have one that is still alive, but I saw the ramshorns killing one of them before my eyes and I've seen two other Assassin shells that haven't moved in at least a week.

 

I don't overfeed the tank, so I know that isn't the reason for the population explosion of ramshorns.  I have a lot of Java Fern and Anubias in the tank that the snails can munch on with out decimating the plant stock, but my Wisteria and Cabomba can't seem to hold up to those ramshorns.

 

I have pond snails.  They are not so bad.  They do multiply easily and get into the filter, just like the ramshorns, but they only eat rotting plant matter.  As long as there isn't a lot of rotting vegetation in the tank, the pondsnail population can be kept in check.

 

 

Gerald Wrote:

Hi Beeker - please post a pic of your "ramshorn" snails.  The behavior of yours does not sound at all like the small red & brown Planorbis ramshorns that many of us keep without any problems in planted tanks.  Perhaps yours are the S. Amer Marisa  (Colombian ramshorn)  which is really a type of apple snail (Ampullariidae) with a ramshorn-shape. 

 

Sand:  I like medium-grain sand, about 0.5 to 2 mm diam, brown or gray-brown when I can find it.  I usually gather my own from sandbars in streams, and sift it through a screen to get out any trash and larger particles.   Soil under the sand is fine for your shiner/darter/livebearer tank, but sunfish may dig it up.  If you want soil in the sunfish tank I would use it only with potted plants, then lay some large flat stones around the base of the plant so the sunnies cant dig it out as easily.


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#2 Beeker

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Posted 31 January 2015 - 05:46 PM

Here's a picture.

 

Attached File  IMG_0845.JPG   67.1KB   0 downloads



#3 gerald

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Posted 01 February 2015 - 09:42 AM

I keep Planorbis (ramshorn), Physa (bladder snails) and Lymnaea (pond snails) in many tanks with live plants and have not noticed any apreciable plant damage.  Might depend on the exact plant species, snail species, and whether enough other foods are available.  Beeker your snails look like Planorbis - I'm pretty sure they did not kill your assassin snails - more likely it died for other reasons and the ramshorns ate it.   And like junebug says they usually eat algae and dying leaves, not healthy leaves ... unless they run out of other food.  


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"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#4 Beeker

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Posted 01 February 2015 - 07:16 PM

I don't want to hijack this thread, but if you are certain that these are ramshorns, than I cannot explain what I've been seeing.  I have watched them go after other snails and kill and eat them.  I have also watched them eat healthy leaves.  They have killed my Tiger Lotus Bulbs. 

I'll have to look into it.

They are well fed.

 

I think we have a difference in terminology. Here is what I call a ramshorn snail:

 

RamshornSnail.jpg

 

This is what I get in my pond. I get a billion of them and they eat everything in sight. Iris, Lillies, Cattail, Hornwart, Water Lillies, you name it. Tears them to shreds. I hate what they do to my water lilies. The full grown ones are a good centimeter to 13mm in diameter.

 

In the attached photo are two other snails. The top one is what I've always called a pond snail, or aquarium snail. They're harmless. They multiply, but get the right fish and they're snacks. I had some in my 30 that came in on some plants and my angelfish made quick work of them and their eggs. They get about 5mm at the max. When I think of "snails" in aquariums, the kind that multiply and everyone hates, this is what I think of.

 

The one on the bottom is also a ramshorn snail but I'm not sure what the heck it is. Looks to me more like a terrestrial snail I see around here under damp logs in the woods and in the soil after a good rain. They showed up after I decreased the water flow in my 100 and never went away. I had a real slack water problem and I got a massive outbreak of hydra, BGA, and these guys. The hydra and BGA are gone, but the snails stayed. They're all over the place. The biggest one I've seen is about 2mm though, small enough to be food for my flagfish. He loves them.  :D/

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#5 gerald

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Posted 01 February 2015 - 08:54 PM

well ... they look like my little ramshorns ... but maybe they're a different species with very different behavior! 

Do yours get about 5/8 - 3/4 " across when full-grown? reddish-brown with no obvious stripes, and no operculum?


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"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#6 Beeker

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Posted 02 February 2015 - 12:26 PM

well ... they look like my little ramshorns ... but maybe they're a different species with very different behavior! 

Do yours get about 5/8 - 3/4 " across when full-grown? reddish-brown with no obvious stripes, and no operculum?

 

 

Yes.

Could their behavior changed due to inbreeding for so many years?

Perhaps they've gotten used to eating leftover fish food and now like the protein?

When one of the fish from the tropical tank dies, I remove them and put them in the snail tank.  The ramshorns devour them quickly, the pond snails don't touch them.  I also see the ramshorns eat other snails, shell and all, if the other snail is injured.  When I see them go after another apparently healthy snail, usually I see them climb onto the shell and start chewing on the shell first, weakening it, and then climb down to the body of the snail, start climbing into the shell partially, and trying to eat it alive. 



#7 gerald

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Posted 02 February 2015 - 04:26 PM

Weird ... even Rosy Wolfsnails dont eat the shells of their prey.   I can believe the protein attraction part; most aquatic snails will eat dead animals. But I really doubt they've mutated through inbreeding enough to develop the behavior and anatomy required to kill other snails and eat shells.  Seems more likely they are a carnivorous type of ramshorn (which I never knew existed, except Marisa which is not a true ramshorn).  Where did you get them from? Are they a N.Amer native snail? 

 

In fairness to the OP, I am moving these "Carnivorous Ramshorn" posts to a new thread.


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#8 junebug

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Posted 02 February 2015 - 06:07 PM

I've seen my ramshorns climb inside a mystery snails shell.  A few snails died, and before I could remove the shells, the ramshorns and bladder snails ate them.  Now they go inside the shells every now and then to scavenge for food and explore.

 

Mine also crawl on each other's shells all the time, but they never "eat" the shell.  They suck debris off it and then move on.  They also climb on each other's shells during mating.

 

I have seen them eat seemingly healthy plants, but then again I don't know the consistency of the leaves of a slightly ill java fern.  I do know for a fact that they have never eaten any of the baby plants coming off the ferns.  Ever.  I see the babies floating in the tank every now and then after a plant gets munched by a snail, so I assume that the plants have had trouble adjusting and had dying leaves.

 

Maybe you could take a video of your snails doing these odd behaviors?  I agree with Gerald, they are certainly planorbis spp.  It would be really something to see them killing another snail.



#9 gerald

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Posted 05 February 2015 - 01:49 PM

I think the tiny ramshorn may be a different genus.  The large one could be either Planorbis, Planorbarius, or Helisoma, and I think the small one could be either a Gyraulus, Menetus, Promenetus, Planorbula, Biomphalaria, ...  they are flatter than the big ramshorns, and crawl with the shell tilted over to the side, rather than vertical.  There are several hundred ramshorn species.  The usual ramshorns (red or brown) in the aquarium hobby are European species, probably Planorbarius corneus.  Strangely, I dont see any mention of escaped Planorbarius populations in N. Amer -- hard to believe, as widespread as they are in hobbyists tanks.

 

The pond snail (bladder snail) in strat guys pic is Physa.  Lymnaea are also called pond snails, but their aperture is on the opposite side from Physa.  (Physa are sinistral, Lymnaea are dextral)  and at least some Lymnaea can be live-plant eaters.

 

Here's a good reference for eastern N. Amer species:  http://www.fwgna.org/index.html

 

 

What you have there is a big ramshorn, a bladder snail and a baby ramshorn.  I'm guessing something else is eating your plants, though, because ramshorns don't eat them unless they're already dying.  I have them in every one of my tanks save for one, and that's only because I happened to have to bleach all of the plants I put into that tank.

 

Regarding pea gravel, no idea where you're getting your info, but I'm a member of numerous groups and forums online and while some people tend to prefer sand, not everyone does.  Gravel is fine and much better for planting, as it allows the fish waste to get to the plant roots and fertilize more efficiently.  Sand makes root tabs necessary.


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"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#10 strat guy

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Posted 05 February 2015 - 08:12 PM

Thanks for that, big help for me. Yeah the little guys carry their shells on their side, and like I said, the biggest ones I've seen are only about 2mm. I still think those big rams horns are what eat my pond plants. If one of my yellow flag iris dips into the water, its a goner by the next day, covered with snails. Same with lily pads. I can easily scrape 10 or 15 off the bottom of a pad and its stem during the heat of the summer. Subsequently, the lilies lose their leaves like crazy. The snails eat the roots off hemerocallis too. I have to protect baby shoots on my Arrowhead. If I protect them, they do fine. Once they're above the water surface, no issues. Below the water, snail food.

 

I hate them, they're everywhere.


Edited by strat guy, 05 February 2015 - 08:15 PM.

120 low tech native planted - Blackstriped Topminnow, Central Stoneroller, Fathead minnow, Golden Shiner, Black chin shiner, Carmine Shiner, Emerald Shiner, Sand Shiner, Spotfin Shiner, Orangethroat darter, Johnny Darter, and Banded Darter.


#11 Beeker

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Posted 05 February 2015 - 08:45 PM

I was thinking that maybe these snails were going after the shells of other snails because they weren't getting enough calcium.

Any thoughts?



#12 gerald

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Posted 06 February 2015 - 11:01 AM

Yes, that makes sense, although most sinking pellet fish/invert foods do contain calcium. 

Is your water extremely soft? (less than 30 mg/L GH hardness?)


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Hangin' on the Neuse
"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#13 gerald

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Posted 06 February 2015 - 11:11 AM

My guess is that your ramshorns are something different from the common (European) aquarium ramshorn.  There are species keys on the FWGNA website, but they are for local species only, so if you have no clue where the snails came from originally then the keys may not work.  (Also you may have to dissect snails and examine with a scope to use some of the key couplets).   Good luck!  Meanwhile, be careful not to let any escape into local waters (via nets, buckets, discarded pond gunk, etc).


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"Taxonomy is the diaper used to organize the mess of evolution into discrete packages" - M.Sandel


#14 Beeker

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Posted 06 February 2015 - 01:14 PM

No.  I've been told by my landlord that the water is hard.  BUT, there is fluoride in the water, which binds to and destroys calcium.  I'm wondering if that would cause the snails to supplement their calcium intake by eating shells.  Also, if their shells are already weekened by the fluoride in the water, they would be more suseptible to attack by the other snails.



#15 gzeiger

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Posted 06 February 2015 - 10:33 PM

I'm in the process of moving and don't have any to look at right now, but my gut feeling is that that doesn't look like ramshorns I've had. The whorl of the shell gets big too fast. Native species I've collected would have at least two more rings in a shell that diameter.

 

Not sure how careful your estimate of adult size is either, but ones I collected in SC got twice the shell diameter you stated.



#16 gzeiger

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Posted 06 February 2015 - 10:34 PM

I should note that the maximum size was rare in the wild, but didn't take long to achieve in captivity.



#17 Beeker

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Posted 07 February 2015 - 03:10 PM

The snails in my picture are still small.  They don't get full size in that tank, as they get eaten either by fish or each other.



#18 junebug

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Posted 24 February 2015 - 05:06 AM

I've seen those tiny snails before.  Had them in several tanks.  They never touched my plants unless there was melt, and I found as they matured their shells turned upright like a normal ramshorn.  I just assumed they were a different variety of the common ramshorn snail.



#19 gzeiger

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Posted 24 February 2015 - 06:05 PM

Small ones that as far as I can tell look identical to yours are native and moderately abundant in western Washington state.






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