How to Plant and Grow Hornwort in Your Fish Tank
By Eddie Waithaka @aquariawise
Hornwort is a submerged, free-floating aquatic plant that is popular in the aquarium hobby, though it is considered an invasive species in some places.
The species is often used as a floating decorative plant in freshwater (both coldwater and tropical) aquaria.
Hornwort attaches itself to the substrate or aquarium objects and spread its fluffy, filamentous and bright green leaves in a way that adds interest to the fish tank. And also provide excellent cover for newly hatched fry.
The plant is an easy-freshwater aquatic species to grow and will tolerate a range of water conditions hence ideal even for beginners.
Hortwort also has a fast growth rate and is easy to propagate with impressively hardy stems that recover quickly, growing new leaves only a few weeks after damage.
Grow your hornwort plant in at least 15-gallon aquariums filled with soft water with a temperature anywhere from 59°F to 86°F and a ph of 6.0 to 7.5.
That being said, today we’ll look at everything you need to know about hornwort, from how to grow, hornwort plant care, propagation and much more.
Hornwort Overview
Ceratophyllum Demersum, commonly known as hornwort, rigid hornwort or coontail is a species of Ceratophyllum which grows submerged and free-floating in freshwater fish tanks.
This aquatic plant reaches a length of 10 feet and has side shoots that make it large and bushy.
Consequently, the features play a huge part in making hornwort a good background plant in aquariums.
Hornwort is widely spread across the globe and grows in lakes, ponds, and quiet streams. It also does occur in the entire USA and Canada.
Intrestingly, a hornwort plant doesn’t develop roots and instead attach to the substrate and decorations via the bright green leaves growing in whorls of six to twelve.
On the other hand, though hornwort is a popular aquatic plant in aquariums, in the wild it is a cause of numerous problems hence considered an invasive species in countries like Newzealand.
The plant is particularly infamous for out-competing native plants due to its allelopathic abilities. However, in closed environments like aquariums, these abilities help hornwort growth by access to more space and nutrients.
By and large, hornwort is a flowering plant with both male and female parts found on the same plant. However, the flowers are not the most colorful hence won’t create any outstanding thrill in your fish tank.
In comparison, hornwort is closely related to mosses and liverwort.
How to Grow Hornwort in Your Aquarium
Hornwort doesn’t grow roots, so it’s not exactly feasible to start it in a substrate. However, the leaf-like projections on the plant will normally attach on gravel or sand and anchor the plant to the bottom of the tank.
There is a high likelihood that your plant will rot if you intentionally force it to start in the substrate. Therefore, consider floating hornwort in the water which is faster and easier anyway. Then let the plant attach to surfaces on its own.
Alternatively, use suction cups and nylon thread or airline tubing to fix hornwort to the glass near the tank bottom to hold it in place instead of putting it in the substrate directly.
Floating hornwort is pretty straightforward, simply throw it in the tank and wait for your plant to thrive. The plant will effectively pollinate under water and continually develop with no much need for human assistance.
Hornwort bloom with small flowers, wherein some species, flowers blossom in clusters.
How to Care for Your Hornwort
In the wild, hornwort grows in lakes, rivers, streams, ponds and even in swamps. This diversity hence make the plant quite versatile meaning it can grow in a range of aquarium setups.
This includes anything from small 15-gallon tanks through the medium sizes like 30-gallons all the way to big tanks that are over 70-gallons.
However, limit your hornwort to tanks above 15-gallons since the plant grows quite fast and may easily outgrow smaller tanks.
Hornwort will thrive in a wide range of temperatures as well, anywhere from 59°F to 86°F meaning you can plant it in both coldwater and tropical tanks. The plant loves soft water with a fairly neutral ph of around 7.
That said, there are no special requirements, but due to the plant’s rapid growth, hornwort quickly diminishes nutrients in the fish tank so you may need to add fertilizer occasionally.
Lighting: Is Hornwort a Low-Light Plant
Hornwort is not a low-light plant and will struggle if grown in less than 8 hours of lights a day. This plant does best under moderate to high light about 2 to 4 watts per gallon, with too little light resulting in plants that have elongated stems and a few leaves.
Also, instead of growing your hornwort in high light, I recommend growing it in medium light because plant growing under heavy light get overly bushy; besides, more light will encourage algae growth.
Allowing hornwort access to too much heavy light will also turn your plant yellow.
Simply put, hornwort plants grown under high light will develop albeit to rapidly, so be ready to do a lot of pruning.
Hornwort Tankmates (Compatibility)
Hornwort is a hardy plant with leaves that grow back quickly in the rare instance they are nibbled, which means the plant makes a good companion for almost all freshwater aquarium fish.
Nonetheless, hornwort benefits more fish than others.
Fish that lay their eggs on plants, those that love low-light and timid or docile species do particularly well in aquariums planted with hornwort.
However, the plant could become food to some herbivorous and omnivorous fish like gouramis and angelfish, so you’ll want to keep such species at a minimum.
Shrimp and loaches are great with hornwort because they eat algae growing on live plants and any other food edible debris stuck on hornwort.
Generally good hornwort companions include shrimp, mollies, guppies, livebearers, tetras, and corydoras.
Hornwort Propagation
Like most hardy aquarium plants, propagating hornwort is fairly easy. Simply cut a piece from an existing plant and replant it in another section of your fish tank.
In fact, instead of cutting new pieces from your plant, you can replant pruned stem tops to start new hornworts.
Also, side shoots removed from a mother plant, or even any other part, can be used for hornwort propagation.
As I’ve mentioned before, replanting hornwort s not hard either because this is a free-floating aquatic species. All you have to do is put the cutting in your aquarium, and soon enough, a new plant will establish gradually.
That being said, hornwort growing in the wild propagate via vegetative fragmentation. Which means, any part of the plant that separates from the rest, whether artificially or naturally, will form a new plant.
This could be a potential challenge when you don’t want more than one hornwort plant in your fish tank.
However, this type of natural propagation is mostly present in wild plants but less common in closed environments like in aquariums Hence, this should not be a serious problem, but keep an eye out just in case.
Hornwort Aquarium Benefits
Below are 3 benefits you get when you add hornwort to your aquarium.
#1— Hornwort Absorbs Chemicals (Nitrate Buster)
Hornwort absorbs chemicals and minerals that accumulate in aquariums from fish waste and tap water where the plant is especially an epic nitrate buster.
However, like other aquatic species, hornworts will absorb ammonia before nitrates. The other chemicals hornwort expel from fish tanks include carbon dioxide and phosphates.
These waste products, which are nutrients to your hornwort, are then converted to food by the plant cells
The hornwort plant, notably clean aquariums better than other species because of its rapid growth which means quicker nutrients absorption. Therefore, use hornwort when you need to supplement your filter or in a filterless aquarium setups.
#2— Hornwort Helps in Breeding
Hornwort grows fine-dense leaves which when coupled with its floating nature make a great place for fish to lay their eggs.
Most fish eggs will stick on the plant instead of getting lost in the substrate or devoured by adult fish. Also, hatched baby fish find refuge in the thick hornwort foliage in the first few days of their lives.
Moreover, some fish like neon tetras need their eggs to start in dark breeding tanks for them to hatch since they’re light dependent. Hornwort thus play a huge role by creating this environment using a thick floating foliage cover.
#3— Water Oxygenation
When hornwort and other and other aquatic plants metabolize, they take in carbon dioxide and expel oxygen into the water which is then breathed by the fish in your aquarium.
Which means, hornwort doesn’t just supplement your aquarium filter but also the air pump. Still, the plant does this better than other aquarium plants due to its fast-growing capabilities.
Hornwort plants will be especially useful in heavily stocked tanks or in an aquarium with no air pump.
My Two Cents
Hornwort is a hardy and easy plant to grow even for beginners. Plus its notably more efficient at cleaning the fish tank than most aquarium plants.
Therefore, you should consider hornwort if you are going to add live plants to your fish tank.
However, think about the size of your tank before placing hornwort in because this plant grows fast and can easily max out your aquarium.
Finally, remember to prune your plant regularly to keep it well groomed for visual interest. And to ensure it doesn’t get too bushy to an extent it’s out-competing your fish for space. The fish should have enough areas to swim and play in.
Enjoy your planted aquarium.
