Hepper is reader-supported. When you buy via links on our site, we may earn an affiliate commission at no cost to you. Learn more.

Can Goldfish Eat Duckweed? Vet-Approved Nutrition Facts

Lindsey Stanton Profile Picture

By Lindsey Stanton

goldfish swimming in tub full of duckweed

Vet approved

Dr. Luqman Javed Photo

Reviewed & Fact-Checked By

Dr. Luqman Javed

DVM (Veterinarian)

The information is current and up-to-date in accordance with the latest veterinarian research.

Learn more »

If you’re thinking of adding duckweed to your aquarium or pond, you might be wondering if your goldfish are going to nibble on this plant, and if it’s safe for them to do so. The short answer is that yes, your goldfish can eat duckweed, and most goldfish love eating duckweed!

Let’s find out a little more about this plant.

aquarium plant divider

What is Duckweed?

Duckweed is also known as Lemnoideae (or Lemma Minor) and is one of the most popular plants for goldfish tanks. It grows naturally in lots of different places across the world, including the USA, Europe, the Far East, and the UK.

It has bright green leaves, which range from 1 mm in size to over 6 inches. Duckweed’s natural habitats are wetlands, marshes, streams, ponds, lakes, and rivers.

Image Credit: angnokever, Shutterstock

aquarium plant divider

How to Keep Duckweed in a Goldfish Tank

Duckweed grows incredibly fast, and more so if your tank has a bright light on for some or all of the time. It can need regular pruning to stop it from completely taking over. Some goldfish will eat it so fast that it doesn’t get a chance to establish itself, though! The only way to tell which way your tank will go is to give it a try.

Image Credit: DVY714, Shutterstock

You shouldn’t need to add any additional fertilizer for the duckweed, as it will obtain all the nutrients it needs from the water in your tank, with the added bonus that your tank water will be much cleaner! The plant also helps remove some of the nitrogen waste your fish produce (ammonia), making them a useful addition to most goldfish tanks. Individual strands of duckweed generally live for around one year, unless they’re eaten by your goldfish first!

The good news is that it reproduces nearly as fast as it grows, so as long as you have some new growth coming in, your tank shouldn’t need restocking. To err on the safe side though, you should always keep some duckweed in a separate container (in the scenario that your goldfish eat the plant faster than it grows).

Duckweed is somewhat fragile when it comes to being handled. It’s safer to use a small net and move the duckweed around to where you want it than handle it with your hands.

It is important to note that because it grows so fast, and is a surface plant, it can often deny light for your other planted tanks in an aquarium. Maintaining a small divider on the water surface to ensure your plants underneath also get enough light might be recommended. Its rapid rate of growth also makes it especially useful for new tanks, as it easily outcompetes most forms of algae that grow in a new aquarium.

How to Keep Duckweed in a Goldfish Pond

Duckweed will quickly take over a pond if there aren’t any goldfish to eat it, so combining the two together can work great! Koi, tilapia, and grass carp will also eat duckweed.

Where to Buy Duckweed

Any aquarium retailer should carry duckweed, but it’s also available online. It’s a cost-effective way to add some greenery into your tank and reduces the cost of buying goldfish pellets. Once the duckweed has established itself in your tank and your goldfish are eating it, you can usually reduce the amount of pellets and other food you give them.

While it might seem tempting to take duckweed from your local pond, this isn’t a good idea because it can introduce parasites or other pathogens into your tank.

aquarium plant divider

Wrapping It Up

Duckweed is an easy-to-grow aquatic freshwater plant that goldfish love to eat! As well as providing nutrition for your fish, duckweed can also help remove waste and nutrients from your tank water, improving the water quality and reducing the need for cleaning.

It can grow extremely fast, so limiting light and removing some of the weed is recommended if it’s starting to cover the surface completely. Some goldfish love duckweed so much that this may not be a problem; in fact, you might find yourself having to add more duckweed if your fish eat it all before it gets a chance to reproduce!

Adding duckweed to a goldfish tank or pond is a great way to add some enrichment for your fish in the form of a tasty green snack. Inexpensive and easy to find, duckweed can make a great addition to your goldfish tank.

See also:

Featured image credit: Sorakrai Tangnoi, Shutterstock

Related Articles

Further Reading

Vet Articles

Latest Vet Answers

The latest veterinarians' answers to questions from our database