Vallisneria gigantea, commonly known as Giant Vallisneria or Tape Grass, is a popular aquatic plant species that is native to various regions around the world. It is characterized by its long, ribbon-like leaves and tall growth. Here is a detailed description and care guide for Vallisneria gigantea:

Description:

Vallisneria gigantea has long, linear leaves that can grow up to 1.5 meters (5 feet) in length. The leaves are typically green in colour, but they can have variations ranging from light green to dark green. The plant develops a strong root system that anchors it firmly into the substrate. It produces long, slender runners that spread horizontally, giving rise to new plants.
Female plants may produce white or yellowish flowers on long stalks that emerge above the water's surface.

Care Guide:

Lighting: Vallisneria gigantea requires moderate to high lighting conditions for optimal growth. Provide at least 2-3 watts per gallon of full-spectrum light to ensure sufficient light penetration.

Water Parameters: Maintain a water temperature between 22-28°C (72-82°F). The pH level should be slightly acidic to slightly alkaline, ranging from 6.5-7.5. The water hardness can vary, but a range of 3-12 dGH is generally suitable.

Substrate: Vallisneria gigantea benefits from a nutrient-rich substrate.
Use a fine-grained substrate that allows the plant's roots to spread easily. A layer of nutrient-rich substrate can be added during planting or supplemented with root tabs.

Nutrient Requirements:
Vallisneria gigantea is a heavy feeder and requires regular nutrient supplementation. Liquid fertilizers or root tabs can be used to provide essential macro and micronutrients. Carbon dioxide (CO2) supplementation is not necessary but can promote faster growth and denser foliage.

Water Flow:
Moderate water flow is beneficial for Vallisneria gigantea. It helps distribute nutrients to the plant and prevents debris from settling on the leaves. However, avoid strong water currents that may uproot or damage the plant.

Propagation:
Vallisneria gigantea readily propagates through runners. The plant sends out horizontal runners that produce new plantlets at their nodes. These plantlets can be carefully separated from the parent plant and replanted to propagate new individuals.

Compatibility:
Vallisneria gigantea is generally compatible with a wide range of fish and invertebrates. It provides shelter and hiding places for small fish and fry.
The dense growth of the plant also contributes to water filtration and oxygenation. Regular maintenance, such as trimming of damaged leaves and removing runners where necessary, will help maintain the health and appearance of Vallisneria gigantea. Monitor the plant for any signs of nutrient deficiency or excessive growth, as well as the overall condition of the aquarium or pond. With proper care, Vallisneria gigantea can create a beautiful and natural aquatic environment.