Guadeloupe naiad, small-toothed

Family: Najadaceae. Distribution: widespread, found in the water bodies of the Americas. Genus: Najas. The entire plant is submerged. Whorls of leaves occur on a long brittle stem. Sometimes the leaves are opposite. Leaf blades are linear. Flowers form in the leaf axils.

Appearance: the length of the dark-green leaf blade with small serrations along the margins is up to 2 cm, its width is 0.15 cm. The leaf apex is rounded, slightly bent backward.
Old name - Najas microdon. One of the most hardy and undemanding plants. Forms dense lacy stands in the water column. Widely used by aquarists as a substrate for fish spawning. Placed in the background, Najas creates a beautiful backdrop for plants with large leaves. Grows steadily throughout the year.

The water temperature at which Najas feels satisfactory can vary within fairly wide limits - from 18 to 30°C. It can be kept in tropical and moderately warm aquaria. Water hardness does not play a significant role, but in very soft water the plant develops somewhat more slowly. The active reaction (pH) of the water can be any. Partial water changes 3-4 times a month are desirable, as Najas grows better in fresh water.

As for lighting conditions the plant is comparatively undemanding, it tolerates prolonged shading, but attractive stands of lush green are formed only under strong lighting.
Both natural and artificial light are suitable for illuminating an aquarium where Najas grows. When using fluorescent lamps of type LB, the optimal lighting power should be approximately 0.4 W per 1 L of volume. Fluorescent lamps of type LD can be used, but in combination with low-power incandescent lamps. The duration of the photoperiod can vary within very wide limits and depends on the aquarium's illumination.

The nature of the substrate does not play a significant role for this plant. Najas can be grown floating in the water column. When planted in the substrate it forms a poorly developed root system that serves mainly to anchor the plant. Najas absorbs nutrients through its entire surface. In this regard neither the degree of siltation nor the type of substrate have a substantial influence on its growth. Mineral fertilization is not necessary for Najas; the plant gets enough substances that enter the aquarium with fish food.

Najas is very easily propagated by cuttings. It is sufficient to take one of the numerous shoots and provide it with more or less suitable conditions to obtain a new dense stand.

The plant can be recommended to novice aquarists not only because it is easy to keep, but also because it can actively influence the aquarium's metabolism, supply fish with oxygen and prepare water for many demanding plants.