Hornwort Care and Maintenance Guide

Aquarium enthusiasts are awed by the hornwort for a number of reasons. First, it boasts of a beautiful green color that looks dazzling in a tank. Secondly, it can grow up to lengths of two feet or more given favorable conditions. Lastly, it is very easy to care for as compared to a number of other aquarium plants. One other point that cannot go unsaid is that the plant is a favorite of a number of fishes. It offers a lovely cover for them when they need a little time away from prying eyes, or bright light.

It is called by a number of names. The most common one is foxtail. This stems from the fact that it looks bushy like the tail of a fox.

Appearance of Hornwort


It has no roots and must be fixed onto the substrate using weights. In its natural habitat, it gets anchored by the base leaves that often act as roots. These usually get fixed onto the water sediment. Alternatively, the plant can be obstructed in free flowing water. If nothing plucks it from there, it stays put and grows to maturity.

The stems of the plant are long, smooth and quite delicate. They can reach lengths of 3m and diameters of 2mm. They are often suspended by branches deep down the sediment. From the stem are green forked leaves that are well arranged in whorls of between 7 and 12. In case the plant is anchored in a substrate, it develops rhizoids.

During the periods between July and September, flowers are produced. Except in very unique cases, the hornwort flower is relatively small, measuring about 2mm. Around it are 8 greenish- brown petals, sometimes more.

After a period of time, a 4mm ovoid fruit bearing three spines are produced. Of the three, one is apical while the other two are basal. Late in the autumn, it may also develop buds. These sink to the bottom of water in winter to form new plants during spring.


The hornwort is native to North America. However, aquarium trade has seen it distributed to almost every corner of the world. It survives in many aquatic locations including marshes, streams, lakes, ditches, ponds and seas.

In the other parts of the globe, they grow in damp or humid locations. Some species of the plant grow as small weeds in cultivated soil or back gardens. In cool temperate regions with tropical rainforests, the plant can be found growing at the bark of huge trees.

The hornwort enjoys high nutrient waters where it settles at the bottom of mud, sand and rocky materials. If these kinds of conditions are maintained in the tank, the plant can become a healthy green.


Scientifically known as Ceratophyllum demersum, the hornwort was discovered by Linnaeus. Its family is Ceratophyllaceae in the class of Magnoliopsida. The Ceratophullum genus was derived from Greek words. The two names ‘Keras’ and ‘phylon’ mean horn and leaf respectively. On the other hand, demersus is Latin, meaning under water.

In the IUCN Red data book, it is listed as LC, meaning least concern.

Importance of the hornwort

It has a variety of uses in the aquarium. This include a source of food to fish. Most fish species like the goldfish find it a useful delicacy for their nutritional needs. They also find the shady plant leaves great for resting.

It is an oxygenating plant. It provides oxygen to the water which is useful for fish. It also has an allelopathetic characteristics and because of this, it is able to excrete substances into the water than inhibit the growth of algae. Hobbyists keeping fish that do not require algae growth would find it very ideal.

It fulfils nutritional needs of baby fish. With its spiky needles, the adult fish cannot bully the juveniles as the needles keep the adults away from them. As it grows enormously, it provides excellent location for fish spawning.

In case a good anchor is not found for it, the plant can be left to float freely in the tank.

Tank Conditions

The hornwort is pretty easy to care for once the hobbyist is able to have it anchored on the substrate. Tank requirements include at least a 30 gallon tank. The hornwort grows at a super-speed and needs enough space to grow. It needs moderate to strong light conditions. This helps it to grow remarkably well. A hobbyist can use natural light or have the tank illuminated using aquarium led light. Addition of carbon dioxide to the tank is not necessary.

It grows constantly and may therefore do with regular pruning. This can be done by use of sharp scissors to trim away the overgrown leaves. Addition of fertilizer is also necessary as it is known to deplete soil nutrients. In case other plants are in the tank, the fertilizer additions should be more frequent (weekly).

It prefers clear water. When the water is crystal clear, its beauty comes out too.

Other tank requirements include:

  • pH of 6.0-7.5
  • hardness at about 5-15dGH
  • temperature between 59 and 86 degrees Fahrenheit
  • sand, mud and/or muddy gravel
  • use plenty of weights to hold it down


It propagates easily through vegetative fragmentation. Naturally, it grows side shoots from the main stem. If these are pinched off and anchored on the substrate, a new hornwort plant begins to grow.

Parts of the main stem can be broken off too. When the pieces are placed at the bottom of the tank, they will grow.

The hornwort rarely grows as a result of seed dispersal. However, when their seeds sink to the bottom of the water and stay there during the winter, in spring these may come up as new plants.

Important Facts to Keep in Mind

When shopping for the hornwort, be sure to get the right plant as most people confuse the varieties. The hornwort can be grown together with duckweed as it makes a good combination. Do not allow for the overgrowth of the duckweed as they will compete for nutrients and light.

The hornwort is as beautiful as it is easy to care for. It is a good tank addition not only for beauty but nutritional value as well.

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