# Duckweed: Desirable or not?



## Dpajr24

I seemed to have acquired some duckweed (best guess). The stuff multiplies like crazy. Is the plant considered undesirable by most?


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## Aquat

I wouldn't say it's 'undesirable'. Since people sell and trade it all time. Yes, it does multiply like it's name suggest, 'weed'. But in my opinion, I dislike it overall, but I do enjoy the root feature it has. Looks good when it isn't covering my entire tank. Especially in my Iwagumi, some slipped in from my last shrimp shipment. But I net most of them out.


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## totziens

They're nuisance to me.....


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## Michael

Dpajr, welcome to APC!

I've moved and retitled your thread so that it will get more attention and response.

Duckweed can be useful for reducing light and excess nutrients, and some fish love to eat it. I don't like it myself because it is messy--it sticks to nets, tools, and hands. And it gets tangled in other plants where it looks bad.


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## phoenixkiller

Pretty much it depends on what you're using it for. Most consider it a weed, and try to get rid of it. I can't keep it alive actually, so I am thankful for that. Some use it for shy/timid fish to hide from the light, or to use up nitrAtes when they get too high.

Problem with normal duckweed is that it is so small, you will never be rid of it. I got some (By accident) from 3 different people at 3 different times, but every time it all died.


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## Aquat

phoenixkiller said:


> Pretty much it depends on what you're using it for. Most consider it a weed, and try to get rid of it. I can't keep it alive actually, so I am thankful for that. Some use it for shy/timid fish to hide from the light, or to use up nitrAtes when they get too high.
> 
> Problem with normal duckweed is that it is so small, you will never be rid of it. I got some (By accident) from 3 different people at 3 different times, but every time it all died.


You killed Duckweed?! HOW?!


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## ObiQuiet

I wonder if we could formulate a beginner's rule-of-thumb using duckweed? Something like,

"If duckweed grows, your tank can handle any of these plants...."
"If duckweed doesn't grow, you're most likely missing critical nutrient X"

Seems like it could be a good indicator species for a particular kind of issue, or a particular set of conditions. (Though I don't know enough to say what that might be...)


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## asukawashere

I'm fond of using duckweed as a biological filtration system - it sucks up all sorts of crud out of the water. Then, after it covers the surface, I net it out and feed it to my crayfish, African cichlids, and/or koi, and repeat. I also suspect it's a strong contender as the answer to world hunger (seriously, any edible substance that can double its mass in a matter of days is worth cultivating).

On the other hand, it is far from the most attractive substance in the universe.

So, in short, it has its pros and cons, like anything else.


Aquat said:


> You killed Duckweed?! HOW?!


For one, duckweed abhors a current - any tank with sufficient surface agitation won't allow duckweed to thrive.  Unfortunately, doing so also reduces dissolved CO2, so for a CO2-injected tank, it's not the best choice. Works quite well in my 120g low-tech, though!


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## chagovatoloco

I love duck weed, truth be told most of the things we call "plants" are actually weeds.


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## Diana K

My tanks have only small amounts of duckweed. It gets crowded out by all sorts of other floaters:
Azolla- Totally covers the surface, and there is NO duckweed when the azolla is so full. Azolla is easier to harvest, too. 
Water Lettuce- A little duckweed is still found in the few hollow spots. 
Frog Bit- This allows the most duckweed to survive. 
Water Hyacinth- This also has more hollow spots than Water Lettuce, so there is a bit more duckweed in these tanks. 

A few fish eat it. I have some Filament Barbs that will eat it, so when I have some extra I toss it into that tank.


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## JG06

I have never liked duckweed as an aquarium plant. It grows too quickly, is difficult to control, and can cause the surface to stagnate when it gets thick enough to stop surface circulation.

The only way I got rid of it was accidentally introducing tilapia to that aquarium. They ate it with much relish and begged for seconds!


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## agutt

Hate the stuff lol...


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## Flear

i'm still floored with how duckweed won't survive in pheonixkiller's tanks, that's amazing

from my own experience, asukawashere is right, lots of surface agitation will hurt it, well it knocks the roots off. what gets caught in the water filter's outflow has really short roots, ... from about 2" (full length) to about 1/4". never thought it would get short enough to die off though. learn something new 

as for good or bad, ... depends (aside from water surface agitation)

feeding gets a little harder as the duckweed will want to cover the surface
light is diminished, as the duckweed gets first dibs on the light (wants to cover the surface)

if you've got other plants in the tank make sure those plants are getting enough light still.

if you want to get rid of your duckweed, ... i could laugh and say "good luck with that buddy", but it can be done, it just takes time, net it all out make sure you didn't miss any, ... go back in a few days and net out what you missed (yes you did miss some), and continue till it's all gone

if you have no plants, ... duckweed is a cheap plant to have, the roots are rather strait, the bottoms get all squiggly, they don't branch out at all. pond snails & mini-ramshorn snails are found hanging (and sometimes falling) from it (if you have such snails). never seen any of my larger snails on the duckweed

like all plants, plants do what plants do in the aquarium. assist the aquarium ecology

and definition of weed "undesirable plant" difference between "weed" & "herb", ... herb is a desirable plant. but there is no other definition, a weed is not a weed because of the type of plant it is, it's a weed because someone doesn't want it where it is.


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## Aquat

Flear said:


> if you want to get rid of your duckweed, ... i could laugh and say "good luck with that buddy", but it can be done, it just takes time, net it all out make sure you didn't miss any, ... go back in a few days and net out what you missed (yes you did miss some), and continue till it's all gone


Just use a siphon, point the opening end towards the water's surface while it's submerged.

Imagine it getting flushed basically.


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## neilshieh

its a wonder how some people beg for duckweed and cant get it to stay alive :/ for me if i got one plant i'd get 100 floating around a little later. though this is essentially true for all floaters, however duckweed being small gets annoying because it comes up with nets/plants and is ridiculously hard to get off. i usually just use a net and net it all up and then just throw the duckweed away via my hand and a sort of a flick motion to splatter it in my trashcan?
i personally like the bigger floaters such as frogbit and red root floaters, however they too pose the problem of long roots that get stuck in intakes and overshadowing too much.


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## charkes kraft

Goldfish will rid a tank of duckweed. Then you have a goldfish.


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## Dejlig

Duckweed makes me


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## Byork

Makes me mad too! Goldfish are good to get rid of it so are Tilapia but they will eat any thing green or dig/pull it up.


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## Tailfin

I like the way it looks and how helps water quality I mean they do use it for sewage treatment so it must be a good clean up plant. In the other hand though well thats just it its on the other hand my arm my tongs lol.


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## TAB

Does not bother me, I have seen drive people nuts. I personally like letting plants just grow and seeing what happens.

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