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Duckweed is taking over my 20 gallon tank. It's covering the surface completely and blocking light for my Java Fern. Any tips to keep it under control without harming my other plants?

I've had the same issue in my 30 gallon. Duckweed grows like crazy, but you can skim it off the surface daily with a fine net. Just be consistent, or it'll bounce back fast. Also, reducing light to 6 hours helped slow it down for me.

Lol, duckweed is the herpes of the aquarium world. Once you got it, you're stuck with it. I just gave up and let it do its thing. My betta seems to like hiding under it though.

If you're serious about controlling it, try adding floating plants that outcompete it, like Water Lettuce or Frogbit. They're bigger and easier to remove if they get out of hand. Just make sure your filter flow isn't too strong for them.

Vitalix9 wrote: ↑Sat May 17, 2025 1:03 am Lol, duckweed is the herpes of the aquarium world. Once you got it, you're stuck with it. I just gave up and let it do its thing. My betta seems to like hiding under it though.

Yeah, but it's a pain if you're trying to grow other plants. I've found that a surface skimmer works wonders, just gotta clean it out every couple days.

Duckweed can be a nightmare, but it's also great for soaking up excess nutrients. If you're dealing with high nitrates, it might actually be helping. Just skim off what you don't want and leave a little to keep the benefits. My shrimp love grazing on it too.

I've heard some people use a divider to keep it in one section of the tank. That way, it doesn't take over the whole surface. Not sure how well it works, but might be worth a shot.

Agree with Daxtonic. Frogbit is a good alternative. It's easier to manage and doesn't spread as aggressively. Plus, the roots look nice dangling down.

I just remove handfuls every water change. It's not perfect, but it keeps it from getting out of control. My goldfish eat some of it too, so that helps.

Duckweed's a pain, but it's kinda useful if you've got fry. Gives them cover and something to nibble on. Maybe just embrace the chaos?