Growing Pistia stratiotes
Pistia stratiotes is a very popular aquarium plant and has many uses for fish keepers. It is a floating plant that extends its roots into the water column removing nitrates and can also help to dim the lighting for fish species that prefer a dimmer environment, it is also very useful to provide hiding places for smaller species of fish and definitely an asset in breeding tanks for young fry that need to avoid predation from larger fish. Please, bear in mind we have a profile of this plant available after clicking this text - You may find useful information for growing this species there too especially when it comes to water chemistry.
The common name for this plant is “water lettuce” as they do resemble small lettuce floating around the aquarium but I very much doubt that the leaves have the same flavour and indeed could be foul tasting to anyone wishing to try them.
They belong to the family of Araceae and can be found naturally in many tropical regions around the globe. In some areas of the world they are classed as a very invasive species so any unwanted plants should be disposed in refuse bins rather than throwing them in waterways as they can propagate very quickly and overtake other natural species.
They are normally purchased as very small plants but the actual rosettes can reach a diameter of up to 6 inches, their leaves have a green/grey colouration with a texture of succulents as the leaves do hold a lot of water. As mentioned above these plants do develop a large root system if they are healthy and these roots can take up a lot of space in the aquarium if left unchecked, there are many reports of the roots reaching a length of 18-20 inches so as you can imagine in smaller aquariums these roots can become a problem. They can be trimmed with sharp scissors to the desired length without any ill effects to the water lettuce leaving open swimming spaces for your fish.
When first purchased you may see some discoloured leaves especially if you have received your water lettuce through the mail, any leaves that are damaged or discoloured should be removed leaving healthy leaves on the rosette. Many keepers may also experience problems with the water lettuce if they are kept for long periods under extreme bright lighting, you will notice the colour in the leaves fade and the leaves may even start to shrivel, this is a sure sign that the lighting is too bright and should be adjusted accordingly if you wish to keep this plant long term. Pistia stratiotes is a perennial plant and if used in ponds it will over winter, in warmer weather they will produce small yellow flowers but trying to propagate by seed is a difficult task and this plant has found an easier method which is very productive, hence them being classed as an invasive species.
Mother plants will produce stolons which are more commonly referred to as runners which produce baby plants meaning that over time a few plants can eventually cover the surface area of your aquarium or pond if you desire if not then some of the runners will need to be cut away before the baby plants establish their own root system. If you do wish to keep the new plants than leave them attached to the mother plant until they have a good set of roots then you can simply snip the stolon and allow the young plant to take its place in the colony.
As of yet there are no common pests or diseases that affect colonies of this plant so as long as the lighting levels are correct and they have a source of food in the water column you should have no problems keeping and caring Pistia stratiotes in your pond or aquarium.