[Mugatu]

I made the mistake of adding duckweed to my tank when I purchased some new plants at the LFS.

Previous problems were treated with removal via skimming the surface with a net. Unfortunately this time, the same techniques has been fruitless due to my tank being heavily planted. The duck weed is in the moss and everywhere in the tank. out:

Anybody out there with any other suggesions. Other than to completely break down the tank and disturbing the other plants, invertebrates, and fish.

Thanks

 

[hoppycalif]

Duck weed doesn't grow down in the water, only floating on the water. Are you sure it is duck weed that you have, and not something like Riccia?

 

[Mugatu]

Looks like duck weed (it has little roots growing along the bottom and is mostly at the surface). I developed the problem when I was purchasing some riccia. The riccia didn't grow (probably from the Excel dosing.) I figured there were some duck weed in the batch. The problem is that everytime I skim the surface there is alway some caught on my moss and it keeps growing back. Arghhhhh.

 

[hoppycalif]

I have gotten rid of it several times just by using a fish net to scoop out all I can, then repeating it every day until I can't find any more. Eventually I always get the last little leaf. Then I get more plants and here it comes again!

 

[Mugatu]

Thanks. BTW is there any invertebrate or fish that eats the stuff?

 

[hoppycalif]

I understand that goldfish eat duckweed, but I haven't seen that since I don't have goldfish.

 

[davemonkey]

Rainbowfish also eat it, but I'm not sure if they will co-exist with your inverts. I have also read about tiger barbs and mollies eating it. I have mollies and rainbows, but the rainbows always gobble it up before the other fish even realize it's there. (FYI, they will also eat up red root floater.)

-Dave

 

[tkos]

Also check your filter. A piece of duckweed caught in there can lead to a new potential growth source. My filters almost always have some duckweed bits in them.

 

[Robert Hudson]

Duck weed doesn't grow down in the water, only floating on the water. Are you sure it is duck weed that you have, and not something like Riccia?

It gets pushed down by the outflow of the filter, by fish, and by moving things around and it gets caught in plants, moss, algae, whatever, and will live indefinetly that way. Any fine leaf plant seems to be a magnet to duckweed just like it is to algae.

 

[Peyton]

I've gotten rid of it several times by
1. having good surface movement
2. trimming plants before they reach the surface.
3. skim the surface with a net every water change.

 

[Angie]

I love my duck weed. I just thin it out. But mine rarely get in my ohter plants and when it does it does not stay long.

 

[clickbelow.co.nz]

I have 2 of 4 tanks with duckweed I use it for cover to assist with algae control. It doesn't mind huge temperature variance.

Recently I added it to a tank with Keyhole Cichlids 2 Angelfish a Chinese Algae Eater & Black Ghost Knifefish I've just noticed that the other surface plant is doing ok but there is no trace of duckweed (I put heaps in). Best guess the Keyhole Cichlids must be eating it.. great news for me as I produce heaps of it in other tanks. I'll try to confirm whos eating it sometime and hadn't realized it was gone until I read this thread.
I noticed that Rainbows are also supposed to be fond of it.. handy to know as I don't want it in my main community tank.

Duckweed control:

Remove excess regularly if you don't mind it.
If you do mind it.. its tough.. it only takes one piece for it to take over again in time.. I have managed to remove it from tanks by reducing the volume of surface plant and manually removing every trace by hand. Alternatively maybe get Rainbows & Keyhole Cichlids.

If it comes in on plants you buy float them in a bucket of tank water and skim or overflow the surface should help with its removal.

Last time I had a plague of it, it took a solid consistant effort to remove it.. hang in there and on a daily basis search every trace out, you'll win.
Water changes make it hard to get but as I noticed earlier it was correctly mentioned it is a surface plant so doesn't do well submerged.. I think it probably needs its leaves to be able to breathe. In a heated tank its leaves grow larger. I have noticed at times in heated tanks also that there can be a high rate of leave mortality although I don't know if there's a connection.

Surprizingly although its sometimes a curse I actually hunted some out and reintroduced it for surface shade.. it does have uses.
With guppies & white clouds it disturbs feeding somewhat if there is surface current, without current it disperses as food hits the surface.

Hope thats helpful.

 

[Mugatu]

Thanks for all the pearls. I think I am going to end up tearing down the tank and start from scratch. The duckweed is stuck in all the moss and the driftwood. All the sifting in the past week has helped, but it is everywhere. What a nightmare.