Eleocharis dulcis

[Oscar Demonio]

Hi all,

I'm not too sure where to post this, but it's about a plant so I'll post it in the Plant Help section.

I'm currently building a Thailand flooded marsh biotope for Trichopsis pumila, based off various publications I've found online.
I'm trying to source biotope-accurate plants and one of those, which I would really like to find, is Eleocharis dulcis, the Chinese water chestnut.
I'm having a very hard time finding it here in France where I am based, and was hoping you might be able to help me. Do you know where I could find this plant, or do you know someone who might know?
Alternatively, which plant might you suggest to replace Eleocharis dulcis? I'm trying to fill the back right corner of the tank with dense, vertical, stiff "stems" that reach outside of the water, for the fish to swim through and build their bubble nests in.
I purposely made the substrate quite deep in that corner, about 10 cm, with about 20 cm of water above it. The substrate is clay-heavy, and I can fertilise it with root tabs if needed.

Best wishes,
Oscar

 

[Disaronno]

If it is what I think it is, Chinese supermarkets always have it for sale.

 

[Oscar Demonio]

Yeah I've seen it on sale but always processed in some way, either frozen or in cans

 

[Oscar Demonio]

I've seen it being sold on Etsy in the USA but they never ship to France and even if they did it would be prohibitively expensive.
Garden stores don't seem to have it either, so I'm hoping I might be able to buy it off someone who has it in their pond.

 

[MichaelJ]

Alternatively, which plant might you suggest to replace Eleocharis dulcis?

IF you're going for the look of Dulcis (and not planning to eat the plant ) then perhaps Cyperus Helferi might be an option. Can similarly grow emerged and submerged. Just an idea.

Cheers,
Michael

 

[Disaronno]

Yeah I've seen it on sale but always processed in some way, either frozen or in cans

Really? I've always seen it sold fresh. Actually now is a good time to get it as peak season is between fall and new years. Time to hit up other supermarkets!

Cost of shipping it across the Atlantic would be high and import/export customs would be another hurdle.

Oddly enough, never thought of actually growing instead of eating it 🤔

 

[Oscar Demonio]

Interesting! I'll go back and check if they do indeed sell it fresh as well as canned.
@MichaelJ yes I might go with Cyperus helferi for the time being. It's readily available and fits the look, but I'll still keep an eye out for E. dulcis.
Actually, another plant I'm considering is water spinach, Ipomoea aquatica. But it would send the aquarium on a completely different route. It's funny how both the plants I'm looking into for "decorative" purposes are more easily found as food products than aquarium products.

 

[MichaelJ]

Cost of shipping it across the Atlantic would be high and import/export customs would be another hurdle.

Don't go there... it is possible, but the place you buy the plants from will need to have an expensive blanket phytosanitary certificate in order to ship live plants from the USA to Europe. If they don't, you will have to pay for the incidental inspection and that will set you back a bunch of money for customs clearance. And regardless, if there are snails or anything else prohibited found among the plants it will be destroyed - definitely not worth it. Of course, you could be lucky and it just slips through 🤷‍♂️

Cheers,
Michael

 

[Tyko_N]

Actually, another plant I'm considering is water spinach, Ipomoea aquatica

A really nice plant, I have it growing in a sump with bright light and a clay-rich substrate, and it's doing pretty well. It's easy to prune and propagate by cuttings, so you can control how it looks, preferably you're able to give it a fair amount of headroom though. The only issue is that I'm not sure if you can plant the seeds under water, but if possible they can be started elsewhere and then moved into the tank once the top leaves would stay clear of the water surface.

 

[Oscar Demonio]

I have it growing in a sump with bright light and a clay-rich substrate

Do you support the stems or do you let them grow freely along the surface of the water? Do you have any pictures? I’m always looking for inspiration.
I didn’t plan much head room above the aquarium. I can improvise but I’m afraid the Ipomoea would quickly take over the available space, which isn’t huge.
And do they produce many “aerial” roots from stem nodes into the water column? Would be a desirable feature to create a dense environment.

My local Asian supermarket sells some pretty large stems that I could probably propagate by simply placing the ends in the aquarium. I’d have to start dosing feet’s heavily I think. My plants are already showing signs of nutrient deficiency the way it is now.

@MichaelJ Nooooo I really don’t want to start playing that game. Trying to keep it cheap and low stress! 🧘‍♂️

 

[Tyko_N]

Do you support the stems or do you let them grow freely along the surface of the water? Do you have any pictures?

They were just some plants that had been growing outside over summer, that I moved inside when the weather got colder. I haven't supported them with anything yet, but will probably have to give them something to climb soon. Outside, or in very bright light, they get stocky enough to support their own weight, and can grow straight up. Any nodes that get wet sprout a huge amount of roots, while dryer parts tend to stay root-free in my experience.

Mine gets most of their nutrients from the substrate, so you could probably just give them some root tabs every now and then. I'll try to take a couple of photos this weekend.

 

[Disaronno]

I can improvise but I’m afraid the Ipomoea would quickly take over the available space, which isn’t huge.
And do they produce many “aerial” roots from stem nodes into the water column?

Ehh IIRC, the Ipomoea will create a very large and thick carpet mat of roots. I don't think it will work out well for an aquarium. Also it thrives in hotter climates.

Not too fond of the taste either.

 

[_Maq_]

I might go with Cyperus helferi

For me, Cyperus does not grow above the surface, the leaves are winding just below, like a Vallisneria.
What about Eleocharis sp. montevidensis? Sadly, I don't think it grows naturally in Asia...

 

[Oscar Demonio]

Ehh IIRC, the Ipomoea will create a very large and thick carpet mat of roots. I don't think it will work out well for an aquarium. Also it thrives in hotter climates.

that sounds similar to what I read about ipomoea. Forms dense stands of marginal vegetation. I think it could work in a dedicated aquarium and would be a really interesting ecosystem to look at below water.

Any nodes that get wet sprout a huge amount of roots

That’s really really cool! The roots could host lots of micro faunal growth and the stems could break up the lines of sight for gouramis to defend their territories.
Next project ✅
Lots of tropical floodplain lakes actually have these dense mats of floating vegetation that detach from the edges as waters rise, and it would be really fun to try to replicate I think. But I imagine I’d need a lot of space.

For me, Cyperus does not grow above the surface, the leaves are winding just below

Ah, that’s a shame. Maybe another species of Cyperus could work? I’ll have a look at what grows in Thailand, beyond the region I was originally looking at. Maybe it’s also a question of depth of water. An aquarium could be too deep to encourage this genus to transition to emersed growth, and it just stays submerged.
E. montevidensis doesn’t seem to grow in Thailand. I would really prefer to stay biotope correct but I might need to be more flexible. Don’t let perfection be the enemy of good.

 

[Oscar Demonio]

Update: I was finally able to get my hands on some Eleocharis dulcis corms through my brother and I'm growing them out in a large vase before adding them to the gouramis' aquarium.
The water level in the aquarium is a bit high for E. dulcis according to the growing advice I was able to find online, so I might have to lower it or find a way to raise the soil level where it'll be planted, or just see if it'll tolerate the high water

 

[Tyko_N]

The water level in the aquarium is a bit high for E. dulcis according to the growing advice I was able to find online, so I might have to lower it or find a way to raise the soil level where it'll be planted, or just see if it'll tolerate the high water

It'll probably want a fair amount of the leaves above the water surface, as long as you can give it that everything should be fine. Water height recommendations might be for young, or un-established, plants, though and if you can keep the level lower in the beginning that may help, you can raise it later once the plants start to take off. E. dulcis is on my list of "try in the future" plants, so I'm looking forward to see how yours do.

 

[Oscar Demonio]

I'll keep you updated on the dulcis growth. I planted them in potting soil and flooded the vase to saturate the soil with water. They seem to be doing fine for now, and have already put out a few leaves. I'm thinking of transferring them to a closed setup to increase humidity, and use an artificial light because the sun just isn't doing the job these wintery days.

The only reservation I have with lowering the water level is regarding water circulation and temperature regulation. Trichopsis pumila like their water quite warm, so I keep the aquarium at 28 degrees C but I need a water pump to circulate the water and keep it evenly warm, while also maintaining a low flow environment to simulate their natural environment. I'm using a Dennerle Eckfilter Nano at the moment (great filter, super silent) with the spray bar angled backwards towards the glass, but I have to keep the water level above 30 cm to keep it fully submerged, accounting for the substrate depth under the spot I keep my filter. It's not a great solution, as I can feel temperature differences with my hand when doing maintenance/water changes. I'll experiment with angling the spray bar towards the aquarium (duh, as intended) and see what effect that has on water temperature and fish behaviour.
I haven't yet found a tiny pump I'm satisfied with, that would allow me to drop the water level to around 15cm, ensure proper circulation for temperature regulation but not produce excessive flow in the aquarium.
Alternatively, I was also having a look at terrarium heating mats but according to what I read they're not well suited for aquariums.

Anyways, the gourami seem happy, as they laid their first batch of eggs this weekend already and I suspect I may have some fry swimming around in the tank by now.

 

[Oscar Demonio]

Update on the Eleocharis dulcis.
The shoots started appearing a couple days after I planted the corms in water-saturated potting soil. There are 7 corms total, so I'm still waiting for 2 to germinate.
They seem to be growing relatively well (given my previous experience with plants), but I think the humidity is too low for them in my house, so I moved their container to an empty aquarium that I could close with a glass lid. The humidity should increase as the water in the vase evaporates. I will also start spraying them regularly to keep the leaves moist. Lighting is from the window and two Nicrew lights I had lying around.
I'll wait for the all of them to have sprouted and grown at least 10 cm before raising the water level.
Glasses are for scale