Plant Care.
Aquarium plants also need regular attention. Be sure to thin out aquarium plants, thin out floating plant thickets so they do not interfere with normal lighting access for other plants. They should not occupy more than one third of the surface. Trim the leaves of plants that have reached the water surface; otherwise, they will fill the entire water surface and block light from other plants. You also need to closely monitor plant shoots so they do not climb into the plantings of other plants, crawl into the foreground, and ruin the intended design.
Dead leaves should be removed immediately. With dense growth of young plants formed on creeping shoots, old individual specimens should be removed, thinning out the planting. Creeping shoots with young plants that have penetrated into an area occupied by another species must either be cut off or turned back into their own area, rooting the young plants there. Plant transplantation that disrupts the root system should be done as rarely as possible.
If plants with a shortened stem have overgrown significantly to the sides, crowding out surrounding plants, the large outer leaves should be removed. Plants with a shortened stem, prone to forming floating leaves on long petioles, are periodically trimmed until underwater leaves with short petioles begin to grow. Long-stemmed plants (for example, гігрофіла Hygrophila) generally strive toward the water surface. Usually, they grow to the water surface and then stretch even higher or creep along the surface. In this case, the lower part of the stem is often relatively or completely devoid of leaves and looks unattractive.
For plants with an elongated upright stem that have reached the water surface, it is necessary to cut off about half of the stem, which can be planted as a cutting in place of the parent plant. If the growing tips of these shoots are cut, they will also begin to produce side shoots and branch out. As a result, instead of one long thin stem, you will get an attractive bushy plant. Cut plant parts can be used as cuttings and grown into new plants, and they can be used to fill empty spaces.
Some plants (for example, валіснерія Vallisneria) propagate by shoots and can quickly fill the entire aquarium with their lush greenery. Such thickets need to be thinned out regularly. Plants with an elongated upright and flexible stem do not grow above the water surface; their stem bends and continues to grow, creeping along it. In case they darken the plants located underneath or the aquarist does not like it, the stem is cut and planted as a cutting instead of the parent plant.
If there is too much light in the aquarium, hair algae (thread algae)—greenery in the form of thin threads that entangle aquatic plants—will develop on the plants. Remove the hair algae. The amount of light needs to be reduced. If green plaque appears on the walls or objects in the aquarium, clean them and reduce the lighting time or intensity. If plants do not grow or leaves rot and fall off, lighting should be increased. Sometimes in old tanks, root rot is observed in aquatic plants. In this case, one has to resort to a complete water change and thorough washing of the sand.
Plant Fertilization.
Whether or not to give fertilizers is a complex and individual question. Usually, aquarium plants have plenty of nutrients produced as a result of 
fish activity. As “food”, plants consume nitrates formed from fish waste products. However, even in tanks with plants, fish-keeping efforts are mostly aimed at removing excess nitrates through regular partial water changes. In most aquariums, the ratio of fish to plants is higher than in an equivalent volume of natural water. In addition, aquarium fish tend to produce more waste than their wild relatives due to overly generous feeding. Therefore, think about whether you really want to introduce additional nitrates into your aquarium in the form of artificial fertilizers.
Plants are able to actively extract the substances they need from the external environment. Hydrophytes are more dependent on the environment than terrestrial plants, which receive most of their nutrition from the soil, because unlike them, they absorb nutrients through their entire surface. The concentration of nutrients in the water can fluctuate within quite wide ranges. The plant organism, extracting these substances from the external environment, creates their necessary concentration in the tissues.
If these substances are sufficient in water and soil, the plant develops properly, grows rapidly, blooms, and bears fruit. With a shortage of one or more necessary substances, growth retardation is noted, the plant shape changes, and reproduction stops. Sometimes an excess of certain chemical elements is observed in the water, which can also cause impaired plant development.
The unsatisfactory condition of plants can be caused not so much by a lack of nitrogen and other macronutrients, but by a deficiency of micronutrients (iron, manganese, boron, etc.) also necessary for their vital activity. Therefore, introducing small doses of aquarium complex fertilizers with an emphasis on the micronutrient component is hardly going to hurt. If your plants do not look very good, despite the presence of nitrates in the aquarium water, this problem probably has nothing to do with nutrient deficiency.
If you still have to use fertilizers, preference should be given to slow-release granular fertilizers. They need to be applied into the soil under the roots of plants rather than added directly to the water; clay balls are also sometimes placed under Cryptocoryne.
Substrate Cleaning and Algae Removal from Soil. Snail Removal.
Proper Aquarium Care is the Key to Its Inhabitants’ Health. 
