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Family: Alismataceae

Common Name: Ozelot Sword

Origin and Habitat: The Ozelot Sword is cultivated hybrid developed by a nursery in the former East Germany. Ozelot Swords are a cross of Echinodorus schlueteri 'Leopard' with Echinodorus barthii. This hybrid results in a plant having marbled areas on green leaves. Depending on the variety of Ozelot Sword, the marbled leaf areas may appear as a red wine color to almost black. Young, new leaves are the darkest, with individual leaves fading to a light green as they age, although the marbling pattern remains. Increased lighting and optimal conditions yield more intense coloration on new growth. Easy to care for and very vigorous if nutritional requirements are met, the Ozelot Sword is an excellent plant for the beginner.

Ideal position in aquarium

Typically smaller that the common Amazon Sword and possessing eye-catching leaf color, an Ozelot Sword makes an outstanding centerpiece specimen. While an Ozelot Sword's vigorous growth can take over a tank, with pruning an Ozelot Sword is easy to manage. Placement in the back or middle of an aquarium is optimal. Given the rosette growth form, an Ozelot Sword may easily reach the width of a standard 29 or 55 gallon tank.

Lighting requirements

Ozelot Swords tolerate a wide range of lighting conditions. While optimal growth is obtained under medium-high light and with pressurized CO2 injection, Ozelots survive quite well under low-medium light and no supplemental CO2. In low light, leaf marbling is retained, but coloring is less vibrant.

Growth rate


Minimum Tank Suggestion

20 gallon / 75L

Water parameters for Ozelot Sword

Ozelot Swords tolerate a range of water conditions. Water pH and hardness are not critical. Ozelots reportedly will tolerate small amounts of salt. Supplemental nutrients, particularly iron, are recommended since Ozelots are heavy feeders. An enriched/enhanced substrate with iron is recommended and they benefit from regular fertilization. In addition to liquid fertilization, root tabs may be useful to enhance growth. pH: 5.5-8 Hardness 2-16 dH (Water hardness not critical) Temp: 20-28C (68F-83F) Size: 40cm (15 ") Growth Rate: Medium/fast Placement In Tank: Mid to Background


Growing from 10 to 20 inches (typical 15 inches/40 centimeters) the Ozelot Sword may be grown submerged or emersed in a riparium. Ozelot swords grow at a moderate to fast rate. Even under average conditions with no CO2 supplementation, a new leaf per week is not uncommon. When grown emersed, the leaves are thicker and take on an ovoid shape. Submerged leaf growth has elongated leaves, more broad and not as long as those of the Amazon Sword. Leaf growth is more horizontal than the Amazon Sword, resulting in a larger horizontal footprint closer to the substrate.

Propagation is by rhizome division or adventitious shoots (flowers and daughter plants). When mature, Ozelot Swords may form natural "splits", forming a second crown. To fully divide this crown, gently extract the plant from the substrate and cut along the natural division. Ensure that each new crown piece has sufficient roots! Emersed plants frequently produce flowers that are self-fertile, but flowering is less common for submerged plants unless stimulated by long photoperiods. When exposed to an extended (12+ hour) photoperiod, presumably mimicking the summertime photoperiod, Ozelot Swords send up adventitious shoots that will extend above the surface. Between flowers on the shoot, plantlets will form. If kept submerged, these shoots will produce more daughter plants and no flowers. Note that adventitious shoots will form at other times, but with lower frequency. When removing daughter plants, be careful not to damage the adventitious shoot since the lower daughter plants may mature before plants that are near the tip of the adventitious shoot. Do not remove the plantlets until they are two to three inches (5-7.5cm) long for best results. If you wish to propagate by seed, be prepared for additional work. You will need to assist the plants by pollinating the flowers with a horse-hair paintbrush and eventually collect the seeds. The seeds can be germinated using peat or compressed peat pellets, but the moisture level must be kept high and the seeds exposed to direct sunlight. Germination takes approximately two weeks followed by an extended period of slowly raising the water level as the new plants grow. Note that growth from seed is a slow and low-yield method of propagation.

Some of the most beautiful and useful plants for the tropical aquarium are found among the Echinodorus, a genus distributed in the tropical and sub-tropical regions of the Americas from the lower United States down to Argentina; the two "African" species of Rataj are almost certainly erroneous (Kasselmann, 2003). Echinodorus derives from the Greek echinos [hedgehog] and doros [pipe or hose] referring to the spiny fruit. The English common name of "sword plant" comes from the general lanceolate shape of the leaf of most species and is generally used for all plants in this genus although other non-Echinodorus plants may sometimes appear under the name "sword."

Larger-sized species have a rhizome, whereas smaller species are stoloniferous. All species are perennial or annual aquatic or marsh plants found in boggy flood areas or along the banks of stagnant or slow-flowing waters. Except for the very few species that are permanently submersed, Echinodorus plants spend half the year emersed (when they flower) and the remainder submersed during the flood season. Leaves arise in a rosette and can be very variable not only between emersed and submersed forms but also when cultivated under different conditions. Correct identification often requires study of the flower. Inflorescences (flower stalks) are formed in all species; when grown permanently submersed in the aquarium most species will not flower but plantlets (daughter plants) will develop from the nodes on the inflorescence.

Confusion exists over the number of species, and many have been known under different names. In his revision of the genus, Rataj (1975) listed 47 species. A major revision by the botanists R.R. Haynes and L.B. Holm-Nielsen (1994) lists 26 species. In 2004, Rataj increased the number of species to 62. More recent work by Samuli Lehtonen--incorporating cladistic analysis using morphological data--has proposed 28 valid species (Lehtonen, 2007).


Haynes, R.R. and L.B. Holm-Nielsen (1994), "The Alismataceae," Flora Neotropica, Vol. 64, pp. 1-112.

Kasselmann, Christel (2002), Aquarium Plants [English translation by Ulf Kotlenga].

Lehtonen, Samuli (2006), "Phylogenetics of Echinodorus (Alismataceae) based on morphological data," Botanical Journal of the Linnean Society, 150, pp. 291-305.

Lehtonen, Samuli (2007), "An integrative approach to species delimitation in Echinodorus (Alismataceae) and the description of two new species," Kew Bulletin Vol. 63, No. 4, pp. 525-563.

Lehtonen, Samuli and Leena Myllys (2008), "Cladistic analysis of Echinodorus (Alismataceae): simultaneous analysis of molecular and morphological data," Cladistics, Vol. 24, No. 2 (April 2008), pp. 218-239.

* Thanks to Byron for some of the above information and editing assistance!

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