Water lettuce (Pistia stratiotes), also referred to as water cabbage, or Nile cabbage, is an aquatic plant that can be surprisingly difficult to grow in the home aquarium. But with a little bit of hard work, these plants form an attractive maze of hanging roots, which creates the perfect environment for fry and skittish fish.
It is believed that water lettuce is native to Africa, though there is no consensus on where it originated from on the continent. It was first recorded on the Nile River, near Lake Victoria. In the ensuing years after its discovery, it has spread around the globe.
This plant is grown locally (Malta) by one of our partner aquarium plant keepers/breeders. The currently available plants have a diameter of 7 to 10 cm and you will get 1 plant with each unit purchase.
Water lettuce grows up to 25.5 centimeters, though it tends to be smaller in the home aquarium. Its leaves have no stem and their surface is covered in short, soft hairs, which help to trap air and increase the buoyancy of the plant.
Water lettuce grows floating on the surface water, and its leaves form a rosette, with dense, submerged roots beneath it. These plants grow like a weed outdoors, but they can be very challenging to grow in the home aquarium. However, if they are provided with the right conditions, they can completely overrun an aquarium, and in most cases, it’s a good idea to remove a few plants during weekly tank maintenance.
A regular set of full spectrum T5 or T8 bulbs is sufficient to grow these plants, but as most water lettuce available for sale are grown in shade, they should slowly be introduced to full light. If they are placed under strong lights immediately after being purchased, it’s likely the leaves will scorch, and the plant will struggle to grow.
Water lettuce can propagate both sexually and asexually, though sexual reproduction is exceedingly rare in the home aquarium. The flowers are tiny and are located at the center of the plant. Each plant will only have either male or female flowers. If successful fertilization occurs, a small, many-seeded green berry will form.
Asexual reproduction is far more common in the home aquarium, and smaller daughter plants will form floating beside their mother plant, connected by a short stolon. When they reproduce with this method, they can form dense mats, and it’s important to not let them completely cover the surface of an aquarium. If they do, they will prevent light from reaching other plants, and can even suffocate the fish beneath them.
Introducing Water Lettuce
When these plants are first purchased, they will often have numerous dead, yellow leaves. These leaves should be removed before adding the plants to the aquarium, ensuring the plants is primed for rapid growth. It will often start out slowly, but will begin to spread and grow very fast when mature.