Water wisteria (Hygrophila difformis) is an easy and undemanding aquatic plant that is used by beginner and experienced aquarists alike. Its quick growth, combined with its hardy nature makes it one of the most common plants available in the aquarium hobby.
Water wisteria is native to the Indian subcontinent and can be found in India, Nepal, Bhutan and Bangladesh. It mainly grows in shallow water and is either rooted or floating on the water surface. Most of its growth occurs during the rainy season in the wild, but it will grow year round in an aquarium.
It is a relatively small aquatic plant, and most will only grow to a maximum height of 20 inches (50 cm) and a width of 10 inches (25 cm). In aquariums with lower light, it may be considerably smaller with narrower leaves.
Because of its size, it makes the perfect addition to the mid ground or rear of an aquarium. It can also be used as a carpet plant if it is placed on its side, and rooted in place. This will cause the leaves to only grow on the side facing up, and will provide a carpet effect at the front of the aquarium.
Water wisteria is very easy to care for, and its only true requirement for luxuriant growth is rich substrate or failing that – fertilizer tabs. While they will grow best under high lighting conditions, they will still do well under low lighting.
Some people insist that the addition of CO2 is an absolute must for water wisteria, but in my experience they will still thrive without the addition of any CO2. However, their growth may differ greatly depending on the water chemistry in your area.
When choosing a substrate for water wisteria, the best option is usually to purchase a specialty plant substrate. With that being said, they will still do well in small grain gravel if they are provided with root tab fertilizer.
If you decide to choose a sand substrate, the water wisteria will have to be anchored by something until the roots have time to grow into the sand. Until the roots are fully developed, it’s very easy for the plant to become detached from the substrate.
In the home aquarium, the best way to propagate water wisteria is through plant cuttings. If you remove a stem near the base of the plant, or in some cases – even a single leaf, it will quickly form roots and grow into a new plant.
Water wisteria is compatible with most fish, but its fine leaves means that many large fish will damage the plant if they are kept together. It does best with smaller non-cichlid fish and should never be placed in a tank with goldfish. A goldfish will devour water wisteria in a matter of hours and will leave nothing more than a few lonely stems sticking out of the substrate.