Giant ramshorns as duckweed control ?

[Fishfur]

To my surprise, my giant ramshorns have proven to be outrageous consumers of floating plants, most especially duckweed, salvinia and frogbit.

I put them all in a 5G tank, because they were making a mess of the frogbit in my frog's tank. I had lots of frogbit, it was just getting really beaten up. So I removed them, and the tank they went into had a thin layer of duckweed on it. A week later, it has vanished. I tossed in a fair size handful of young frogbits, since I have more than enough of them anyway.. and tonight only one of those plants remains.

The big female snail.. she's the only one I am sure of in terms of gender, has laid twice since I put them into this tank. They are ignoring big stems of anacharis, but mowing down the floaters. If it weren't that I don't trust them not to eat other stem plants, I'd think of offering these guys as organic duckweed controls for the aquarium.

 

[AbsurdAj]

How many rams did you have in that tank? Because I was thinking of getting a few but I want to know their destruction capabilities

 

[Fishfur]

There are, let's see, 8 adult snails, and no little ones, at least, not 'til some eggs hatch. Most are about an inch across.. two are quite large, closing on two inches across.

I tossed a big handful of fresh frogbit in there last night. This morning every single one of them is hanging upside down from the frogbits, munching as fast as they can and there's a distinct dent in the amount of frogbit.

Who knew they'd be so fond of the floaters ? I wish now I hadn't sold most of my L. major at an auction ! I'll try to get a pic of them.

And I do wonder if it's just they don't like anacharis. They used to be in a 29G that had no plants in it other than anacharis and while I think they must have eaten some of it, they sure didn't eat enough to stop it from growing.

Edit. I have some salvnia minor, and I'm going to toss some of that in too, see if they mow it down as fast. I suspect they will, even their close cousins, the Mystery snails, like a bit of salvinia now and then. Maybe it's just they like soft stuff, but for snails as big as these are, seeing them all upside down on the surface is a bit mind blowing.

 

[shellyx]

My giant ramshorn is exactly the same, I have mine in with my filter feeders and add frogbit to the tank from my elephant nose tank. The snail never stops eating lol always hanging upside down feeding. I stick to java fern in the tank as he seems to leave it alone. But I did learn the hard way!

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[AbsurdAj]

There are, let's see, 8 adult snails, and no little ones, at least, not 'til some eggs hatch. Most are about an inch across.. two are quite large, closing on two inches across.

I tossed a big handful of fresh frogbit in there last night. This morning every single one of them is hanging upside down from the frogbits, munching as fast as they can and there's a distinct dent in the amount of frogbit.

Who knew they'd be so fond of the floaters ? I wish now I hadn't sold most of my L. major at an auction ! I'll try to get a pic of them.

And I do wonder if it's just they don't like anacharis. They used to be in a 29G that had no plants in it other than anacharis and while I think they must have eaten some of it, they sure didn't eat enough to stop it from growing.

Edit. I have some salvnia minor, and I'm going to toss some of that in too, see if they mow it down as fast. I suspect they will, even their close cousins, the Mystery snails, like a bit of salvinia now and then. Maybe it's just they like soft stuff, but for snails as big as these are, seeing them all upside down on the surface is a bit mind blowing.

The reason they didn't eat a lot of the anacharis is probably because anacharis is allelopathic, meaning that they release a kind of toxin that inhibit the growth of other plants (mainly algae). Don't worry though the toxin in general wont affect your rams


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[jetajockey]

The reason they didn't eat a lot of the anacharis is probably because anacharis is allelopathic, meaning that they release a kind of toxin that inhibit the growth of other plants (mainly algae). Don't worry though the toxin in general wont affect your rams


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Do you have a link to some data on this subject? I've seen it thrown around a bit as conjecture but haven't really gotten anything concrete yet. That said, I stock anacharis with a few dozen other plant species and haven't noticed anything, although I haven't been paying all that much attention.

 

[Fishfur]

They certainly don't appear to like anacharis.. it remains untouched even when it is the only green thing in their tank.

Interesting, they leave java ferns alone ? I have to think they would have preferences, which might be species specific or individual, given the floaters they appear to like so much are fairly soft, perhaps some of the stem plants wouldn't be touched so long as they had plants they prefer available instead ?

Don't have all that many different plants to test them with, but I think I will throw in some others, cuttings and such, see what they do with them, after they've wiped out the latest helping of frogbit. I don't mind them eating the frogbit, it grows thick and fast in the frog tank, to the point it shades so much little else grows in there under it.. so having something to feed the excess to is not a bad thing.

Edit.. haven't really looked into allelopathy in water plants but a quick peek brought up this article.. rather technical, but the basic info is that most, if not all, water plants can produce allelopathic compounds, due to intense competition for space and nutrients. I'm more familiar with this in terrestrial plants.. Black walnut trees are one well known example, secreting juglones, which prevent anything else growing near such a tree.
Hard to say how much such toxins might affect fish or snails but they're intended to give plants a better shot at survival overall, so being able to deter an animal from eating it has to be a big advantage for a plant.
http://jlakes.org/web/Allelopathy_aquatic-autotrophs-CRPS2003.pdf

 

[Fishfur]

I checked this morning and two thirds of the big handful of frogbit is already gone. And there is another clutch of eggs too. Seems abundant food stimulates reproduction, which I've seen happen with Mystery snails too, as well as other species.

They appear to be mating often too, I've seen five of them all clustered together for hours, upside down hanging from the floaters, in what I am sure is mating behaviour. So maybe I'll be seeing a population explosion. If so, be nice to be able to sell some.

 

[Fishfur]

Update for those interested in how fast these guys eat. The big bunch of frogbit was entirely gone sometime this afternoon.. I tossed in another small bunch. And there are now 6 clutches of eggs. At least it looks like I'll have some to sell in awhile

Took less than ten minutes for every snail in the tank to latch onto a frogbit after the latest handful went in. Not sure if they smell it, or see it, but either way, they respond very quickly.

 

[Fresh2o]

Water lettuce...how do you think they will like water lettuce? Just curious.


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[Fishfur]

I really don't know. I'd have to get one and give it to them to find out. I used to have loads of it but it all started to grow like mad and got far too big to keep so I tossed it. I'm sure they'd eat the roots, but the leaves on the larger ones are not as soft as frogbit, so perhaps they might not like it as much.

I'll try to get one and see what they do with it, if I can.

 

[Fresh2o]

The water lettuce I have does not get much bigger than frogbit. Outdoors it gets as large as a grapefruit.

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[Fishfur]

Yeah, that's what mine looked like for a long time, and then suddenly it just started growing like crazy.. and got more than five inches tall ! It was in a covered tank with my frog, and it hit the cover and got squashed as it kept on going. It was well on the way to being as big as any you see in a pond, which is why I tossed it.

I don't know why some water lettuce stays small, and some doesn't, because it's the same species in both cases.. but whatever it is, mine just stopped staying small. Bummer, they're really cute when they are little. I'm sure the snails would eat the small version of the plant.. when they get larger the leaves get much thicker and stiff too.. which might not appeal to them so much.