Fish that eat duckweed

[Dirtydave]

I keep giving a friend duckweed and he say is keeps disappearing. The usual supects(koi,goldfish) are not present in his tank.There are some giant daneos,electric blue rams,ember tetras,otociclus,some dwarf gurammis, a few small cat and maybe a few more that I can't remember. What other fish are known to eat duckweed. I've done a ton of research and am coming up empty handed.

[H.K.Luterman]

Does he have heavy flow in his tank? That can actually prevent duckweed from growing. 

[Aquatic Journal]

I mean if a fish gets hungry enough it will probably eat the duckweed. Anything with a big enough mouth that really wants food could come up and eat it especially the catfish depending on what types he has. However, if you are running a sponge filter and he is running a canister or a hang on back that could be the difference. I have a lot harder time growing any floaters with a hang on back then I do in a sponge filter tank. They do not like to get wet!

[Dwayne Brown]

I personally have had both duckweed and water lettuce in my aquarium and have noticed the same thing happen. You usually either have to buy a large amount so that it can clump and grow together, otherwise the duckweed will just flow throughout the aquarium and wont spread. Or get a smaller aquarium with a grow light and grow it in there. 

 

 

[Maggie]

If you have a HOB you can corral off the filter flow area so it won't whip the duckweed around and kill it, if that is what is happening. My HOB killed off the red root floaters but not the salvinia minima, though it does do a number on individual leaves. I corralled it off, but not in time to save the red root. 

[ChefConfit]

Guppys don't go to town on it like goldfish and carp but I've seen mine eat it once in awhile, also some cichlids are known to eat it iirc. But with that stocking list I'd say it's just the flow preventing it from growing

 

[Will Billy]

Back when i had water lettuce and i noticed my gouramis eating the roots of my water lettuce. They eventually plucked it to death. I know its not duckweed but i imagine floating roots look the same to a gourami. 

[Dirtydave]

On 3/12/2021 at 11:29 PM, CT_ said:

I've just heard that as general advice.  sounds like pea puffers kinda have their own rules.  They do seem pretty different from your "average" fish.

I'm no feeding expert, what would you say the optimal amount is? 

 

On 3/16/2021 at 12:55 PM, Tinyfellows said:

Hmm didn’t see anything come in and I’m a member 

 

On 3/21/2021 at 10:42 PM, tekjunkie28 said:

Well for one its a medical device. 2. why would you need to do it?  If you have an air stone the tank will have "enough" oxygen.

As a side not have you ever had an indoor air quality test done?  

 

On 3/21/2021 at 11:35 PM, ChefConfit said:

Running an air stone is a great idea, but I wouldn't run pure O2 through it. A small usb air pump will be sufficient to keep O2 saturation close to 100% iirc. Using your O2 tank would just be wasting money not to mention something you depend on for your health. 

But your thoughts that extra O2 would be beneficial to your tank especially at night is correct especially in a heavily planted tank. At night when there is no light for photosynthesis plants actually consume O2 and release CO2 so very heavily planted tanks can run into problems with low O2 saturation if they are not running an air stone. 

Also O2 poisoning is a thing. It's rare that hobbyists run into it but it does happen. I've heard horror stories of people basically giving their fish the bends because they used very cold water (which can be super saturated with O2) during a water change.

 

On 3/22/2021 at 9:46 AM, Medkow74 said:

Do you live in an area where you have to run a gas furnace or boiler for heat? 

 

10 hours ago, H.K.Luterman said:

Does he have heavy flow in his tank? That can actually prevent duckweed from growing. 

No but if thats the case many people would pay you for that answer to a much discussed problem. Not an issue for me but if I've read it once I've read it a thousand times;once you have duckweed you have it forever .

 

[Dirtydave]

10 hours ago, H.K.Luterman said:

Does he have heavy flow in his tank? That can actually prevent duckweed from growing. 

By the way I have a hob,a sponge filter and an airstone in every tank and it still multiplys.is that not that not heavy flow?

[ChefConfit]

@Dirtydavenot necessarily I have the same in my display tank. If I fill it so the water coming out of the hob shoots straight across the surface of the water rather than a waterfall going into my tank than it whips around all floaters and slowly kills them duckweed included. If I drop the water even a 1/4 in then it reduces flow at the surface enough that the floaters can gather at the other end of the tank and stay out of the outflow keeping the tops of the leaves dry.

Keeping the surface flow really fast to slow/prevent growth and removing what I could by hand let me eliminate duckweed from the tank in about 2 weeks. It hasn't had any in about 6 months now. 

[Dirtydave]

In a couple of my tanks the hob blows the duckweed far under water literally to the bottom and even gets stuck in moss and other plants and it still thrives.By the way I really enjoy the look of this.Pretty green dots flowing all over the place.my original intent of the question is to figure out why my friends tank doesn't seem to support the plant.At this point its still a mystery.