Hornwort

With its fine, forked, stiff needle-like leaves arranged in whorls along the stem, hornwort resembles a fox's tail. It has no true roots: it either floats freely or is anchored by burying its lower end in the sand or wedging it under a rock. It also occurs naturally in the lakes and ponds of Türkiye.

Its biggest benefit is that it feeds directly from the water and grows very fast: it absorbs excess nitrate and phosphate and competes with algae for nutrients. It is very useful in newly set-up aquariums, goldfish aquariums and fry tanks.

• It can be left floating freely; it forms a dense cover at the surface and diffuses the light.
• By lightly burying the lower end of the stem in the sand or anchoring it with a weight, it can be used as a vertical "forest" in the background. The buried part may rot; if this becomes a problem, cut the end of the stem again.

• Light: Moderate; in high light it grows even faster.
• CO₂: Not required.
• Fertilizer: Usually not needed; when nutrients are lacking, the needles turn yellow and fall off.
• Trimming: Because it grows fast it needs frequent cutting and thinning; remove the excess from the aquarium.

The stem is divided into pieces; each piece becomes a new plant.

• Needle shedding: adjusting to a new environment, a sudden temperature change or nutrient deficiency. Shed needles can clog the filter; check the filter sponge during the first weeks.
• Sensitivity to liquid CO₂ (glutaraldehyde) products.
• Do not release into the wild: aquarium plants must not be thrown into natural waters.