Tell me about... Your Most Successful Duckweed Removal Efforts

[PineSong]

Duckweed in two of my tanks completely covers the surface no matter how much I remove on the weekends. It is really getting oppressive looking.

Trying to remove it has been complicated by the fact that there are fry in the tanks and the leaves of tall plants like my sword and aponogeton make skimming the surface hard.

I would like to hear others' successful (or most successful) strategies for removing it. I think I would like to try other floaters that will get less out of control, especially now that I have no more HOBs.

 

[MickS77]

I had duckweed completely covering a 40B with a group of Platies. I started feeding less fish food and they eventually they started eating the duckweed, all of it, hasn't come back since. Resumed normal feeding after that. 

[PineSong]

On 1/5/2022 at 11:07 PM, MickS77 said:

I had duckweed completely covering a 40B with a group of Platies. I started feeding less fish food and they eventually they started eating the duckweed, all of it, hasn't come back since. Resumed normal feeding after that. 

Amazing! I have platies, guppies, and mollies in this tank. I'm so desperate I was thinking about QTing a feeder goldfish and putting him in there to gobble it. I keep trying to feed less and less, but there are fry in the tank and I'm an Italian mom at heart so my platy girls weigh about 2 pounds each and apparently turn their noses up at salad. You're motivating me to try harder!

[Levi_Aquatics]

I had duckweed in a ten gallon, I found that it always kept the nitrates very low which was nice, but i hated getting it all over my hands. I removed all the fish from the aquarium then dumped the aquarium outside, sprayed it out with a hose, and then filled it back up and it was good to go. I did have to net out a couple pieces of duckweed that sneaked by under the lip of the aquarium but now it is duckweed free. Knocking on wood lol.

[xXInkedPhoenixX]

The surface agitation from my 2 air driven sponges killed the duckweed when I had it in my 20 gallon and I was even trying to grow it then. It was also easily manually removed from a 3 gallon tank when my betta at the time didn't like it- but small tanks- easy pickins. 

[Lifeisgood]

Adding more surface agitation helped me remove it from a 125.  I started out scooping it out to feed fancy goldfish in another tank but couldn’t keep ahead of it.  The fish in the tank love the current (dwarf rainbows, Hillstream loaches and Panda Garras and Rosy Barbs) so when I added the power head for them I got an added bonus of eliminating the duck weed!😊

[ShySnail]

My duckweed is currently being outcompeted by frogbit. The frogbit is easier to thin out than the duckweed when I do tank maintenance, but since it grows just as quickly I'm not sure if I'm really all that much ahead with changing one for the other. 😆

[PineSong]

Gee, thanks, everybody. It's a very planted tank so tipping it over in the yard is not an option, but I am looking at this list and thinking I will add another sponge filter and feed less. I am also going to try a comb or hairpick this weekend. It didn't really become oppressive until I removed the HOB and the surface agitation went way down, so I am hopeful this combo will get it done.

On 1/6/2022 at 12:41 AM, xXInkedPhoenixX said:

The surface agitation from my 2 air driven sponges killed the duckweed when I had it in my 20 gallon and I was even trying to grow it then. It was also easily manually removed from a 3 gallon tank when my betta at the time didn't like it- but small tanks- easy pickins. 

One of my heavily impacted tanks is only a 5 gallon and has minimal  plants, so I am hopeful that I can manually remove it if I set up my laptop nearby and can watch videos while I comb it all out. It would be easier if the fry in that tank were not nearly transparent and the size of a grain of rice.

[GardenStateGoldfish]

Goldfish, 

 

if not then lots of hand removing and high surface agitation flow. 

[laritheloud]

The only way I've been successful is to manually pick out duckweed as I see it. If you have a lot, you can try skimming them off with a skimmer or a fine mesh scoop, then throughout the following weeks carefully pick out whatever remains. I only have one tank with duckweed (that I left on purpose) and I've managed to be able to keep it that way.

[isaly]

On 1/5/2022 at 11:43 PM, Levi_Aquatics said:

...but now it is duckweed free. Knocking on wood lol.

Knock on weed.

[Levi_Aquatics]

Yep lol @isaly

[Guppy Guy]

My best method for removing Duckweed is to simply do nothing. I somehow managed to kill duckweed! But of course, I keep salvinia, swords, and a bunch of wisteria, pennywort and pothos without issue.

[Guppysnail]

I’m not sure how helpful this will be to you. I actually tried to grow duckweed and failed. I failed epically at all floaters so I tried duckweed as a last ditch effort. I have surface agitation on the entire surface of all my tanks and lids so it’s humid. Maybe a powerhead on your sponge filter aimed at the surface?

[laritheloud]

On 1/6/2022 at 9:30 AM, Guppysnail said:

I’m not sure how helpful this will be to you. I actually tried to grow duckweed and failed. I failed epically at all floaters so I tried duckweed as a last ditch effort. I have surface agitation on the entire surface of all my tanks and lids so it’s humid. Maybe a powerhead on your sponge filter aimed at the surface?

I don't think duckweed is as virulent as they say, but maybe it depends on water conditions. My duckweed has definitely spread but much more slowly than I anticipated. My water lettuce does much better.

[gardenman]

I bought and use an Odyssea Surface Skimmer to skim off the duckweed. In the photo below you can see it at the bottom right of the photo. You can see where I enlarged the skimmer box openings to accommodate duckweed. It works like a duckweed vacuum. Pretty fun to watch. It can also suck in the occasional small fish or fry though, so you've got to be careful.

Forgot the photo. Here it is.

[EVoyager31]

Doesn't really solve your problem but after much frustration trying to remove it I once used a shop vac to get it all out. Was very effective..and very loud. lol at past me doing stupid stuff. But hey, if it worked...is it stupid? 😄 

[BETTA999]

lol i havent have duck weed problems because i cant even keep duck weed when i want 😅

[KaitieG]

On 1/6/2022 at 8:30 AM, Guppysnail said:

I’m not sure how helpful this will be to you. I actually tried to grow duckweed and failed. I failed epically at all floaters so I tried duckweed as a last ditch effort. I have surface agitation on the entire surface of all my tanks and lids so it’s humid. Maybe a powerhead on your sponge filter aimed at the surface?

Ha!  I was going to say something similar--"Put it in my 20 gallon.  It'll die."  I tried every floater I could get my hands on in that tank, including duckweed several times and they NEVER EVER survive.  They go nuts in the 95 gallon, and they hang in there more or less in the 5 gallons, but that 20 kills it every time!

[PineSong]

On 1/6/2022 at 9:33 AM, laritheloud said:

I don't think duckweed is as virulent as they say, but maybe it depends on water conditions.

It seems to love my little 5 gallon ginga sulphureus tank. It only runs a nano sponge filter and that incandescent lightbulb is the only source of light. I don't have a timer for that outlet, so 11 hours of light might also be a factor!

Since it's now been declared a snow day here, I am going to pull up a chair, my kid's comb (shhhh, don't tell him, he never uses it anyway!), a white five gallon bucket and my Co-op specimen container and I am going to try to remove every bit of this duckweed but not any of my teeny fry. The fry are also the reason I don't try to solve this problem with a goldfish. So tempting that otherwise I would absolutely keep one on hand for this.

 

[Torrey]

I can't grow duckweed fast enough to keep the turtle fed, only takes Karma (ornate ornata) 2 to 3 days to clear the full layer of duckweed like PineSong pictured. It's 9.9 gallons, deepest water is 6".

[Streetwise]

I have used combs, hair picks, nets and skimmers. My issue is trying to save snails and shrimp fry during removal.

[PineSong]

Well, I did it. I used a comb and paper towels. I took the floating plants and triple rinsed them before returning them to the tank. I was careful to dip the comb in clear water in the specimen container to release any fry. Only caught two and they were returned to the tank probably traumatized but unharmed.

I am enjoying this little colony--they were off to a slow start taking a few months to breed and then having drops of 6, then 1 and then 1 and then 4. There are just now starting to be enough fish for them to look like a group.  This photo was taken before I returned the floating plants and replaced the top glass:

 

 

 

Edited January 6, 2022 by PineSong

[2000tetras]

A Hang on back filter will wipe out all your duckweed in a month.

[PineSong]

On 1/8/2022 at 12:13 AM, 2000tetras said:

A Hang on back filter will wipe out all your duckweed in a month.

Well, I had a HOB filter on it until a few weeks ago. I did have less duckweed then, but it wasn't zero or even less than half. I think the prefilter sponge that saves my fry from getting sucked in also saves the duckweed.