The water lettuce plant is an ideal aquarium plant for bigger tanks due to its long roots and large rosettes. The roots can easily penetrate the filter, and it is a good idea to position it on one corner of the aquarium.
The plant is commonly left floating in fish tanks and ponds since it derives its nutrients from the water. It is popularly used to control algae, although it might prevent other aquarium plants from obtaining sufficient lighting and nutrients.
You can pair the water lettuce with many fish species or invertebrates like snails. You want to avoid goldfish, koi fish, cichlids, and other fish that may damage the plant. The plant is fast-growing and hardy, and beginner aquarists will find it easy to maintain it.
Water Lettuce Origin
The origin of water lettuce is uncertain, although it was first recorded in the Nile close to Lake Victoria in Africa. It is distributed across tropical and subtropical regions across the world, and it is regarded as an invasive species.
The plant was first recorded in the US in the 18th century. Water lettuce is common in the southeastern United States, but it is prohibited in states like Florida, Mississippi, and Louisiana.
It has quickly become a weed in nitrate-rich waterways, especially those flooded with fertilizers and sewage.
In the wild, water lettuce is characterized by large, dense-floating mats, where its leaves provide a breeding ground for mosquitoes. The plant is adapted to freshwater, and will not survive in salty environments.
Water Lettuce Appearance
Water lettuce (Pistia stratiotes) is classified in the Araceae family. Its name is derived from its rosettes that mimic small heads of lettuce. The plant can develop extensive colonies that can be difficult to eliminate.
The structure of the water lettuce promotes buoyancy and helps it to become free-floating. It has thick yellow-green leaves that join in floating rosettes. Short hairs shoot out from the leaves to retain water and make the plant buoyant.
The leaves are adjoined like ribs towards the roots, and they create dense mats over the water. Mature water lettuce can have 6-inch leaves.
The water lettuce develops wispy roots that submerge into the water for nutrients. One of the advantages of this plant is that it will grow without soil or substrate. The roots can either be white or black, and they provide hiding areas for fry and shy fish.
Wild water lettuce can measure 10 inches in diameter, although they will reach about 4 inches in the aquarium. Its flowers are often hidden amongst the leaves, and the plant produces rounded berries fertilizers once fertilized.
Water Lettuce Water & Light Requirements
The plant struggles to acclimatize to a new environment, and it will seem to struggle when you first add it to your aquarium. Once the water lettuce gets used to the tank conditions, it will become unstoppable.
It is typical for the plant to be delivered with several yellow leaves. Remove these leaves to prime the plant for rapid growth. Try and order the plant from reputable sources since it can harbor parasites and undesirable invertebrates.
Water lettuce is a tropical species, and you should maintain warm temperatures in the range of 70-80ºF. The plant has, however, been grown in colder climates with sufficient protection. If the room where the aquarium is located lacks humidity, keep the tank covered at all times. The ideal PH range is 6.0-7.5.
Bright light will scorch the leaves on the water lettuce, and it thrives in shaded areas. A standard set of full-spectrum T8 or T5 bulbs should be enough for the plant.
You can tell if the lights are too bright once the leaves begin turning brown or yellow. If the plant is not obtaining enough light, the leaves will become stunted and grow smaller.
Water lettuce will proliferate if the right conditions are provided. If you notice a reduced growth rate, check if the tank water has enough nutrients. You will need a minimum of 10 gallons to accommodate its growth.
Water Lettuce Maintenance
Although water lettuce is a floating plant, it does not like to be drifted around. Water currents in an aquarium will push it around even before they are mature enough to form a dense mat. If your aquarium has a powerful filter, you can corral the plant using a fishing line or a hula-hoop, so that it stays in place.
The challenge with growing water lettuce is that it can quickly overrun an aquarium. Cutting off several stolons or individual plants every week is necessary to keep it in check. Cut the roots as well, and leave only about four inches of the root system. If left to grow, the roots can get entangled in the filter or decorations.
If you want to grow the plant in an outdoor pond, keep in mind that cold winters will kill it. You can overwinter them in containers filled to the top with water or move it to a warm room.
You do not have to provide fertilizers unless your aquarium is low in nutrients. The plant mainly requires nitrates for maximum growth, and it will also absorb ammonia and organic waste from the water.
Do not keep the plant with fish that like to nibble at plant roots. The fish may cause irreparable damage, and kill the water lettuce.
Water Lettuce Propagation
The water lettuce plant can propagate sexually and asexually, although the latter is more feasible in home aquariums.
Sexual propagation relies on cross-pollination across water lettuce mats. Every plant has either female or male flowers, which are tiny and positioned at the center of the plant. A green berry will be produced after fertilization, and it becomes brown as it ripens, resulting in a new plant.
The plant propagates asexually through daughter plants that are linked to the mother plant via short stolons.
This form of reproduction will often result in dense mats covering the aquarium surface. Weed the plant regularly so that it does not suffocate your fish or other plants.
Water lettuce will provide multiple benefits to an aquarium. In addition to controlling algae, its roots present refuge for timid fish and invertebrates and fry.
The plant does not demand a substrate as it is free-floating, but it needs to be tamed so that it does not overrun the aquarium’s surface.