The large number of species available for aquarium use makes it difficult to choose which plants to have in your aquarium. The guidelines presented in this leaflet should help you create an environment in which the aquarium plants and animals can survive and grow for a long period of time with relatively little care or alteration of the environmental conditions.
Generally, plants are used to increase the oxygen concentration in water by removing carbon dioxide from the water during photosynthesis, thus permitting more oxygen to go into solution. Plants that are ideal for this situation are those that have a high photosynthetic rate and do not require that they be rooted in soil for normal growth and development. Elodea (Anacharis), Myriophyllum, and Cabomba are all good aquarium plants because they are bushy, rapid growers that do not need to be rooted and are good carbon dioxide consumers.
Plants, such as Vallisneria and Sagittaria, that can be rooted in gravel are also well suited to aquariums. When rooting these plants, they should be carefully pushed into the substratum so that the crown of the plant remains at the surface. They may be securely anchored with small lead weights, stones, or other heavy, inert material until they have secured themselves with their own root growth. Vallisneria is generally a tall plant and should be planted in the back of large and relatively deep tanks. The Corkscrew Vallisneria is a shorter form that is better suited for a smaller aquarium. Sagittaria has wider leaves that Vallisneria and needs a fair amount of space for normal growth. As such, it should be separated by several inches from other plants and the sides of the tank.
If your tank is not in direct sunlight, members of the genus Cryptocoryne will do well. They are narrow-leafed plants that thrive in temperatures between 21 – 26°C (70 – 79°F) and can endure acidic water. The most common species is C. willisi, but equally good is the dwarf plant C. becketti. If you wish to add some color to your aquarium, C. cordata is a good choice because its broad leaves are red on the underside. In addition, some species of Lubwigia, or false loosestrife, have leaves that vary from green to red in color. Other interesting species that you may wish to place in your aquarium include a species of Myriophyllum that is known as Parrot’s Feather, the water fern Ceratopteris, and the hornwort Ceratophyllum. Parrot’s Feather is a bushy, rapid-growing plant with soft green feathery shoots that are very attractive. The water fern can be either planted in gravel or remain floating and will show an interesting method or reproduction. Be sure to avoid overpopulation of this species. Hornwort will do well under almost any aquarium circumstances.
The use of algae and floating surface plants in aquaria is not recommended because they do so well that they become pests. One exception is the complex green alga Nitella. It is used to form thickets for small fish and other fragile and defenseless species and can usually be kept under satisfactory control. Lemna (duckweed) and Riccia (a type of liverwort) can be used if you wish. These plants are usually rapid growers and excess material can be readily removed if the cover becomes too thick. If both are used together, Lemna may tend to overgrow Riccia. At intervals throughout the year Lemna will appear to die out and disappear, but in a few weeks it will return to its original abundance or even be more abundant. When plants such as Cladophora and Pithophora find their way into an aquarium, it is usually necessary to start over. You will need to discard all of the contents of the old aquarium, since the algae will develop rapidly from the smallest portions that may be left behind. Other species may leave slimy scums and foul odors or materials that are toxic to other life forms in the aquarium. In these cases, the aquarium should be cleaned and the sides scraped with steel wool or a razor blade. It may also be necessary to clean the aquarium with a 2% solution of HCl for thorough sterilization. Once it has been sterilized, a thorough washing with distilled or boiled water will allow the aquarium tank to be used again. The only chemical alternative for algae control is 9.065 g of potassium permanganate added to 3.785 L of distilled water. Used with care, this method will often clear an aquarium of unwanted algae.
Finally, two types of water ferns that are commonly used are Salvinia and Azolla. However, if you choose to use these plants, you should be aware of the fact that these are plants that flourish in warm, relatively stagnant water. If they are planted in a relatively shallow aquarium with a high organic content and are given adequate light and a warm temperature, they will do well. If they are planted in a large, relatively sparsely inhabited aquarium that is well aerated and has a cooler temperature, either form will die out in a short amount of time.
Regardless of whether you prefer rooted or floating plants, your selection of aquarium foliage should be based on how you intend to use your aquarium. This consideration should include the prevailing temperature, the other possible inhabitants, and the size of the tank. In all cases, you should be sure to avoid overcrowding, poor planting, and you should maintain the tank for cleanliness. Contamination, regardless of the source, should be dealt with immediately, before conditions deteriorate to the point where a complete reconstruction of the aquarium becomes necessary.
This guide is also available in PDF format on wardsci.com.
Products Mentioned Above
- Aquarium Life category on wardsci.com
- Elodea canadensis | Elodea densa
- Jungle Vallisneria | Corkscrew Vallisneria
