What are the Best (and Worst) Aquatic Plants for Your Koi Pond?

Fish swimming in a clean pond

What are the Best (and Worst) Aquatic Plants for Your Koi Pond?

No koi pond is complete without some aquatic plants to enhance its beauty and create a healthy ecosystem for the fish. Aquatic plants can act as a natural water filtration system, increase the oxygen level of the water, keep algae at bay, maintain water temperatures, and provide hiding places for the koi. If you are considering a koi pond, Aquatic Gardens is where you can go to buy pond plants.

Helpful Pond Plants

Water Lilies

Water lilies are popular options for koi pond owners. This floating water plant is hardy and can thrive in many parts of the country. Their leaves can keep ice and snow at the top of the pond, providing a layer of insulation to protect koi from fluctuating temperatures. Koi love to nibble the roots of these aquatic plants, so it is best to purchase several of them and incorporate other water plants along with water lilies.


Hyacinth plants are another floating water garden plant. These do an excellent job of filtering water. Hyacinth often has blue or purple flowers that bloom from mid-summer to early fall. As they grow, their root system forms a compact nest-like structure. Be careful not to allow the hyacinth to overgrow; it can quickly choke out other water plants.

Water Lettuce

Water lettuce is a free-floating aquatic plant that provides cover for koi. Koi do not bother to eat water lettuce; they can keep algae at bay in your pond. Each water lettuce can spread up to eighteen inches wide and six inches tall. This water plant features yellow or cream-colored flowers in mid-summer.


Coontail is an underwater plant that needs to be placed in pond-friendly soil. Their stems resemble a raccoon’s tail, hence the clever name. These aquatic plants, also known as hornworts, are helpful oxygenators providing koi cover. Coontail water plants are easy to find, inexpensive, and can survive in full sun or shade.


Nothing beats the elegance and beauty of the lotus. These floating aquatic plants are found in many Japanese koi ponds and need very little maintenance. Ensure your koi pond has total sun exposure for at least five hours a day if you want your lotus plants to thrive. These are best for larger koi ponds, but there are dwarf lotus varieties available too. Lotus water plants provide plentiful shade, and the koi do not eat their roots. The only downside is you have to be patient because the lotus will not produce its first blooms until about one or two years.

Water Poppy

The water poppy can grow in all koi ponds, regardless of size. This water plant thrives when it is submerged about six inches deep. They do a great job of filtering water and softening the edges of your koi pond, enhancing your overall aesthetic. Its contrasting dark green foliage and yellow flowers make it stand out nicely. Even though the flowers last for about a day, the water poppy will continue to bloom throughout the summer.

Umbrella Plant

Umbrella plants are perennial aquatic plants that add an exotic element to koi ponds. They do well in full sun or partial shade and multiply quickly due to their self-seeding process. These water plants can grow between three and six feet tall and up to three feet wide. You must plant them in shallow water and cut back the dead stems in the fall to keep your umbrella plants healthy for the next season. They do not tolerate frost very well, so you may need to bring them inside during the winter.

Water Iris

Water iris are lovely water plants that come in various colors. They are good at filtering water and will not get eaten by your koi fish. These will thrive in full sun or shade and must be planted in moist soil. Water iris bloom from late spring to early summer and can grow up to five feet tall. Be mindful of this aquatic plant because it can quickly overtake a koi pond. Check for their seed

pods after blooming and remove them to prevent the water iris colony from increasing too much.


Horsetail is a hardy aquatic plant that is good at filtering water. They have slender stalks that can grow up to two feet tall. These provide a lot of shade for koi, and your fish won’t eat them. Horsetails are easy to remove if you want to change the look of your pond, making them a versatile choice for any koi pond.

Aquatic Plants to Avoid


Naiads are submerged aquatic plants that many waterfowl eat, but a koi pond is not a suitable place to have naiads. They are primarily a weed that can reduce oxygen levels in the water.


This ornamental water plant is attractive in fish tanks, but it is not an ideal plant for koi ponds. Cabomba is a fragile underwater plant that will end up breaking apart and floating in the water. You will want to avoid getting these for your pond.

Curly-leaf Pondweed

The curly-leaf pondweed is most definitely a noxious weed. When these aquatic plants decay, they can release nutrients that can potentially start an algae bloom. Its decomposing material also depletes your water’s oxygen levels, making it an unfavorable option for koi ponds.


Phragmites are invasive and will trap sediments more than anything else. These water plants reduce the livable habitat of koi, making them a poor choice for any newly constructed pond.


Aquatic plants are a lovely addition to koi ponds, and many of them will promote your fish’s health. We hope this list has given you an idea of what koi pond plants you want. Contact us today if you do not know where to buy pond plants and do not have time to install them yourself. Aquatic Gardens is here to answer your questions, help your koi stay healthy, and make your pond look as beautiful as possible.

If you are interested in keeping your koi pond as healthy and beautiful as possible, then please visit our website for more helpful tips, tricks, and maintenance options.