By Karl Schoeler

AS PUBLISHED IN AQUA NEWS MARCH/APRIL 1994
A PUBLICATION OF THE MINNESOTA AQUARIUM SOCIETY

Almost every hobbyist has at one time or another, had an "Amazon sword". It is widely believed that all of these plants come from the South American Amazon region. However, the distribution is much wider. Species have been collected in geographical areas ranging from Massachusetts to Missouri, from Mexico to Florida and many parts of Central America as well as Cuba and of course most of South America.

The genus Echinodorus is a member if the Alismataceae or water plantain family. Other family members include Sagittaria from North America, Ranalisma from Africa, Baidellia from Europe and North Africa and Alisma which is common to all continents. There are six other genera included in this family but most are either not fit for the aquarium or have been rarely imported. Of all the genera included,Echinodorus is by far the most interesting and variable.

Revisions of the genus date back to 1881 and it has been revised at least three times since then. The most current revision was researched and written by Karel Rataj and published in 1975. During this time Karel Rataj was quite active in aquatic plant research. I reviewed his work on the revision of the genus Cryptocoryne in the Nov/Dec '93 issue of the Aqua News. He also was involved with Thomas J. Horenim in the writing of the book Aquarium Plants (TFH). In addition he revised the genusSagittaria and wrote at least nine other research papers in the mid-seventies. He has been active in aquarium magazine publications, writing articles as recently as 1987 for TFH. Other authors in this area may disagree with portions of his identification of species but he is always referenced in their work.

Of approximately 53 species of Echinodorus currently identified, about half of them will do very well in the aquarium. The difficulty is introducing an emersed grown plant to a submersed environment. Most if not all of the species available to the hobbyist are raised or collected in the emersed state. The economics of aquatic plant growth is that they simply grow and reproduce faster if raised in this manner. So what you see in the stores may be a plant that will look totally different when submersed. Only when it has acclimated and begins to show new leaves will you see its' ture underwater character.

A few of the most popular and interesting species to the aquarist are as follows:
Echinodorus osiris -Rataj from Brazil. A beautiful broad elliptical wavy shaped leaf with the younger leaves almost red. This plant makes an excellent centerpiece. It takes a 12 inch diameter area for proper growth. It reaches 16 to 20 inches in height and the leaves are about 2 inches wide. Interestingly, the Baensch Atlas suggests very hard water. Mine apparently has not read the book as it is in very soft, warm water with warmed, fertflized substrate and centered below two 5000 °K fluorescent tubes in a 75 gallon aquarium. Do not allow Chinese algae eaters to be in the same tank with this delicate leafed plant. This plant is my personal favorite of all theEchinodorus species. Once the plant has 15 to 20 mature leaves the rootstock may be split with a razor blade.

Echinodorms horemani - Rataj from southern Brazil. A beautiful plant with some similarity to E. osiris in that the mature leaves bear a likeness to each other. However, a side-by-side comparison shows the E. horemani to be narrower leafed and the young leaves are green. It is slow growing but will reach a height of 12 to 15 inches with a rich substrate an lots of light. This plant is fairly rare in this area so you may be frustrated in your efforts to obtain it. It is well worth the trouble though. The rootstock may be split after the plant matures but this takes an estimated 9 to 12 months in the aquarium under the best conditions.

Echinodorms uraguayensis - Arechavaleta, from Argentina, Uruguay and Paraguay. I like this plant in a group of three to five. It is a narrow, slightly wavy leafed plant that grows to 20 inches. It needs a fertile substrate and medium to high light. It seems to grow faster in a group. Once the plant has 12 to 15 mature leaves it may be split by cutting the rootstock with a razor blade.

Echinodorus tenellus - (Mart.) Buchenau. Common in waters from Massachusetts to Minnesota, south to Florida and Mexico. An excellent foreground plant which will quickly develop runners and cover an area. E. tenellus is the smallest of the genus. It develops very narrow leaves of 1 to 2 inches tall. Usually the leaves will bend back towards the substrate slightly. Sometimes a dwarf species of Sagittaria is sold as E. tenellus. The identification is made easy by the single leaf vein of E. tenelluscompared to three veins of the dwarf Sagittaria. There may be three varieties of the species depending on which reference material is being used. A fine gravel and sand mix is the best substrate. This plant prefers softer water and lots of light. Propagation is by runners.

Echinodorms amazonicus -(O. Kuntze) Bunch. From Brazil. This plant is often confused with E. bleheri but the leaf veins are quite different. In nature this plant grows underwater. It is not a demanding plant, needing only medium hard water and a reasonable amount of light. Fertilized and warmed substrate is a plus. Propagation is achieved through floral stalk plantlets.

Echinodorus austroamericanus Rataj. From temperate zones of Brazil, Uruguay, Argentina and the higher elevations in Peru and Bolivia. This plant is for those of you who have aquariums for killies and other cool water fishes. It will do well in temperatures of 60 to 70 'F and cannot withstand 77 'F or higher. As with many temperate zone plants, it does not require intense light and will do well with minimum lighting provided the substrate or pot is fertile. This plant is sometimes sold as pygmy chain sword or E. tenellus. It is easily distinguished by the widening of the leaf on the upper third. It grows to 3 to 5 inches in a single rosette but shorter if at all crowded. This plant is illustrated in the April 1987 issue of TFH Magazine.

I have described six of the approximately 25 species of Echinodorus which will do well in the aquarium. Included for your study are drawings of these that come from the Revision of the Genus Echinodorms, Rich.

Many of our society members have had success with the "Amazon Sword" and know that it is not necessary to have substrate heating to be successful with them, it is just easier. However, a fertilized substrate is essential for proper growth and propagation. Reasonably strong lighting will greatly enhance their growth and the addition of liquid fertilizers will help even more. The Chinese algae eater and most species of "plecos" like to eat the leaves of these plants very much so it is advisable to stay with the otocinclus and siamensis types for your algae eating tasks. As the larger Amazons grow it is wise to clip off the outermost leaves as they begin to deteriorate. This will encourage new growth and prohibit any blight from occurring.

So ..... the next time you're in the pet shop, ask to see the Echinodorus!

References

Revision of the Genus - Karel Rataj
Aquarium Plants - Rataj/Horeman
Aquarium Alias - Baensch/Riehl
Aquarium Atlas 2 - Baensch/Richl
A Manual of Aquatic Plants - Norman Fassett
Water Plants in the Aquarium - Ines Scheurmann