Five easy floating plants

Floating plants by far are the easiest plants to grow in the aquarium. Lighting is of little concern because they are so close to the light and they draw whatever nutrients they need from the water. Here are five aquarium favorites:

Ceratophylum demersum, Hornwort

When people first see this plant, often they think it is like any other stem plant and should be planted in the gravel. While it looks like any other bunched stem plant, it is actually a true floating plant that never grows roots. The stems branch profusely with thick clusters of needle-brush like leaves. It is often used in breeder aquariums because it offers excellent cover for fry. You will need to thin out the growth regularly because it will keep growing in layers on top of itself and then the lower layers will start to die off due to lack of light and litter the tank with dead leaves. Studies have also shown that the plant emits a chemical in the water that helps to retard algae growth. The plant is native to North America and tolerant of a wide range of temperatures and water parameters.


There are five species of Duckweed and all share a common appearance: instead of leaves they have a small ‘thalloid’ or plate-like structure that floats on or just under the water surface, with or without simple rootlets. They grow profusely in still water and quickly blanket the surface. The species range in size from barely a pinhead to thumbnail size. It grows requiring little effort and care in the aquarium. In fact it is considered a scourge by many hobbyists filters carry the tiny plants around the tank and get them tangled in the leaves of other plants making it difficult to totally get rid of the plant. One tiny plant will quickly turn into several.

Water lettuce Pistia stratiotes

This is a popular pond plant. Full grown plants may reach the size of your hand with roundish lobe like leaves growing in a star pattern. Mature plants send out offshoots with baby plants creating an interconnecting floating mat. The roots dangle about three inches long. In the aquarium you are limited to using baby plants. Ideally they should be in an open top aquarium with the lights at least six inches above the water. Any closer and the heat from the lights may dry out the leaves.


Bladderwort is a carnivorous plant. It has tiny sacks that trap micro organisms and dissolve them to obtain nitrogen and other nutrients. There are several different species that grow long thread like leaves that intertwine into a thick floating mat. Some larger species are capable of trapping small insects and fish fry. It is an interesting plant that will quickly cover the water surface.

Riccia fluitans

Riccia is a plant that consists of short strand like pieces that interlock together creating a loosely fitting mat. They contain no roots or leaves. It is not usually adversely affected by lights close to the water surface since it is level with the surface or just below it. It is a popular floating plant with fish breeders for its ease of growing and the cover it provides for surface breeders and fry. It is also used by aquascapers to simulate moss. Clumps of it are tied to rock and wood with nylon netting or thread. It grows over the netting and looks like a bright yellow-green moss. It must be kept trimmed close to the netting or clumps of it will break off and float to the surface. When grown this way it needs much more intensive light than it does floating.