Hornwort (Ceratophyllum) belongs to the family Ceratophyllaceae (hornwort). Many varieties are known to grow in slowly flowing rivers, lakes, and ponds, which differ in appearance, for example, in lakes Tanganyika and Malawi, there are compact forms with very hard leaves. The range of hornwort is extensive; this plant lives in all regions of the temperate climatic zone and is found in water bodies from the Arctic Circle to the tropics.
Due to its interesting appearance and ease of maintenance, the plant has become widespread among aquarists. Hornwort has long stiff stems, the root system is not developed, so the plant swims freely in the middle and upper layers of water. Nutrients are absorbed by the hornwort directly from the aquatic environment, the conductive elements of the stem are poorly developed, they contain a reserve substance – starch.
The stem can reach a length of up to 1 m, branched, brittle. The leaves are needle-shaped, finely serrated at the end, collected 6-12 in whorls, ranging in color from light to dark green or reddish, and also easily break off due to lime deposits.
The plant can be fixed in the ground with the help of thin thread-like formations – rhizoids. In addition to retaining the plant in the soil, rhizoids perform the function of absorbing substances.
Ceratophyllum flowers are small, in some species collected in small inflorescences, a monoecious plant. An interesting feature is a pollination under water, which is very rare even among aquatic plants.
Care and reproduction
Ceratophyllum is a fairly undemanding plant with a fast growth rate under suitable conditions, which can be planted with bushes in the ground or left to swim in the water column. It is better to keep the plant in a spacious aquarium and regularly shorten the shoots. Cold-resistant species of ceratophyllum can be planted in ponds, in a cold-water aquarium, or in a tropical one, depending on the origin of the plants.
Hornwort prefers alkaline water from 6 to 15 dGH, acidity in the range of 7.0-7.5 pH. The temperature can be in the range of 17-30 ° C, however, at a lower temperature, growth slows down, and the hornwort stalks fall closer to the bottom.
Plants prefer dim light, the duration of daylight should be 12-14 hours. With intense lighting can grow up to 3 cm in length every day. With a lack of light, the leaves of the plant may crumble, and the edges of the stems will rot. In this case, it is recommended to remove dead parts of the plant, establish lighting, and the hornwort will quickly restore its appearance.
The plant does not need fertilizers, since its leaves absorb nutrients – phosphates, ammonia, CO2 and nitrites – directly from the water. In the conditions of a pond in winter, plants can die off, leaving only shoots, which, when the temperature rises in the spring, grow new stems and leaves. Reproduction of hornwort is not difficult and occurs in a vegetative way. Small fragments of the plant and cuttings easily root in the ground, or, freely floating in the water column, build up new side shoots. To fix in the soil, the plant can be pressed with stones or other decorations.
Species of hornwort
Hornwort submerged, or dark green
The hornwort submerged, or dark green, (Ceratophyllum demersum) is able to grow in a wide range of conditions, lives in nature in reservoirs with a depth of 0.5 to 15 m. Due to its great endurance, its distribution range is very extensive. In some regions (for example, in New Zealand) it displaces local aquatic vegetation, including through allelopathic interaction.
This species has long stems of a reddish hue with dark green leaves. Submerged hornwort prefers pure water. Dregs and small particles easily settle on its leaves, which makes it unattractive, but on the other hand, the plant thus acts as a biological filter. Heavily contaminated shoots can be removed from the aquarium and rinsed under running water. The leaves are hard, so Ceratophyllum demersum is suitable for aquariums with cichlids.
Hornwort semisubmerged, Hornwort underwater, or Hornwort light green (Ceratophyllum submersum) – an unpretentious plant, different from hornwort dark green with soft and flexible leaves, each of which is divided into 6-8 shares. The most important hallmark is the fetus. Undemanding to water parameters, able to exist in the temperature range from 5 to 30 ° C, hardness 5-24 dGH. In bright conditions, reddish leaves appear.
Mexican hornwort Ceratophyllum submersum “Mexiko” – a variety of hornwort light green. According to the conditions of detention, it is similar to other species of hornwort – it is rather undemanding to the conditions, has a fast growth rate, and is best suited for tropical aquariums with moderate hardness water. Growth is seasonal and slows by winter.
In the Cuban hornwort (Ceratophyllum spec.), the Internodes are short, plentifully covered with foliage. Like other hornworms, it is extremely hardy. According to the conditions of maintenance and use, it is similar to the other varieties. The growing season continues in winter, without a dormant period. The stalk of a Cuban hornwort may take on a reddish hue. Because of the fluffy branches it is the most decorative, reminiscent of the appearance of a Christmas tree.
The use of hornwort
In nature, hornwort serves as food for herbivorous fish and birds. It is also used as food for domestic waterfowl.
Regarding the use of the hornwort in an aquarium, there are both opponents and supporters of growing this plant. In this case, it is optimal to proceed from the overall design of the aquarium and the tasks of the aquarist. Many note that the plant is indispensable at the first start-up, where it helps to establish biological balance, absorbing the waste products of aquarium inhabitants. In addition, it releases oxygen, as a result of which the accumulating organic matter quickly decomposes.
Ceratophyllum is suitable for both cold-water and tropical aquariums. Hornworms are unpretentious, grow extremely fast (from one shoot per month a plant up to 1 m long can form), they are easily restored after the death of leaves even from a small twig, and therefore are excellent for beginner aquarists.
It is recommended to place the hornwort in an aquarium if an algal outbreak is noted in it. The plant acts as a food competitor to algae and will contribute to the rapid cleansing of the aquarium from them – this is one of the methods of biological control of algae. However, in this case, algaecides should not be used, since ceratophyllum is very sensitive to their content in water, which can lead to its death.
In addition to its decorative effect, hornwort is also valued for acting as a biological filter on which suspended particles, residues of feed and algae settle. If the plant loses its attractiveness, just rinse it under running water or remove too contaminated parts.
However, a high growth rate can serve poorly if ground cover plants are present in the aquarium that do not tolerate shading and lack of nutrients. The leaves and stems of the plant are brittle, and when they die off, they can serve as an additional source of organics, therefore it is necessary to monitor the cleanliness and timely clean parts of the plant with a net, as well as cut too long stems.
In an aquarium composition, hornworms are most often used to decorate the side and back walls, as well as to hide equipment. Hornwort thickets look great in the background with other long-stemmed plants.
This beautiful plant can serve as food for herbivorous species such as goldfish.
Thin hornwort leaves are a good refuge for small aquarium fish and fry, among them some fish can lay eggs, so the plant is also often placed in spawning grounds, where it serves as an additional source of oxygen and shelter.