Should be good as animal feed in limited quantities or for compost or mulch. And you can't keep duckweed in a Goldfish tank because the fish will eat it before it can establish itself.

BUT, that is the only con I have... it is attractive, a great nitrate sponge, grows anywhere no matter what the lighting is and provides some cover for the fish, as well as an anchor for their bubble nests. Some of the benefits of duckweed are – They are good natural food for some of the fish like Koi, Goldfish, and Grass Carp. You can see how this type of food is favored for chicken feed which in turn produces chicken manure which in turn becomes a fertilizer which then can be added back to the water as a food source for the duckweed!
Duckweed is the common name for Lemna Minor. Is duckweed good for a pond? Some of the benefits of duckweed are – They are good natural food for some of the fish like Koi, Goldfish, and Grass Carp. It isn't just fish that eat duckweed though. Because of this, duckweed infestation often contributes to poor pond health. I’d use whatever species you have locally- and harvest it 2-3 times a week in the summer so as to pull those nitrates and phosphates out of the water for good. Without this algae, nutrient levels will explode, creating unhealthy algae blooms and significant buildup of organic debris in the pond (the sludge layer). Duckweed appears to be potentially a major resource for the poultry industries of developing countries and could be incorporated into poultry diets on a least cost basis. If colonies cover the surface of the water, then oxygen depletions and fish kills can occur. Duckweed on a pond. She maintains duckweed is bad, full stop, and always wants to fish it out anytime she sees it.

Good food resources for your gold fish / koi, Duckweed floats and require little structural fibres (5-15%), it has more nutrition by weight compared to other vascular plants: protein (15-25% in natural conditions, 15-45% when cultured under ideal conditions), fat, nitrogen, and phosphorus. Well, I bought some duckweed (lemma minor) and got it established in my tank. Fish and submerged plants can be killed. Like Like These fish love duckweed so … It gives shade to the pond. Keep me posted!

Grass carp look upon duckweed as a food source and may eventually clean up the duckweed in a pond, but are... Koi. Perry, any duckweed species is a good one when it comes to water remediation. Also with these duckweed i never change my aquarium water as recommended by others. I have about 90% coverage from Duckweed.

Duckweed is a good natural filter for a pond as it can absorb bad materials out of water. Duckweed can tolerate a wide range pH, between 4.5 and 7.5, as well as temperatures between 68F (20C) and 86F (30C), making duckweed a … When I got back, the fish seemed fine.
The thick mass of duckweed can possibly serve as a shade for your aquarium, helping to reduce the rate of evaporation of water from your tank and maintaining a cool tan environment. I think I do have a bit more lighting then I need, but now with the duckweed coverage I am not seeing the pearling I used too.

Duckweed could be a good dietary supplement and nutrient source for humans, livestock, and fish. They multiply rapidly and quickly fill any open surface of water unless regularly cleared. So do I need the duckweed coverage? The tiny, rounded leaves float on the water surface, resembling a mass of young cress plants. I'm not such an antiduckweed guy.

Just be sure if you do get it that you don't mind it in all your tanks. Seems to me it provides useful shade, consumes nutrients away from algae and fish can eat it if they get hungry.