So you don’t have to fight with… later
Plant diseases are usually associated with water aging, substrate rotting, improper lighting, deep planting, temperature discrepancies, hydrochemical discomfort, and exposure to toxic substances. The main causes of plant death include chronic lack of lighting and carbon dioxide in the water, as well as the absence of certain mineral nutrition components. As soon as a plant enters conditions different from optimal, it seems to freeze for a while due to stress, then rapidly degrades, and if the cultivation conditions do not match optimal requirements at all, it soon dies. Other aquarium inhabitants—fish and snails—can also harm them by nibbling on the plants.
One of the causes of aquatic plant death is stress associated with improper transportation out of water. Do not let leaves, stems, and roots dry out; they must remain in a moist environment. Such plants will not take root and will die. A plant intended for transportation is placed in a plastic bag with a small amount of water at the very bottom (so that the water does not break the plant during rocking), tightly closed, tied, and placed inside another. The second bag is inflated with air and also tied, which protects the plant from breakage. It is important that the plants do not overheat and become “cooked”, nor overcool. A transportation temperature of about 20°C suits most plants. A transportation temperature of 20°C suits most plants.
Stress developing as a result of changing maintenance conditions for plants that previously grew in natural landscapes is largely related to lighting conditions, primarily the intensity and spectral composition of the sources (which is why plants seem to stop growing when lamps are changed), as well as the mismatch between the hydrochemical regime of the aquarium water and natural water conditions.
A high level of nitrates and nitrites in the home water body due to insufficient water movement and high concentration of living organisms compared to the natural biotope can lead to poisoning and plant death. Therefore, plants, primarily Cryptocoryne, should be illuminated as brightly as possible for 12 hours a day for the first two to three weeks after transportation and placed in water bodies with running water.
A adaptation period of two to three weeks allows wild plants to adapt to aquarium conditions with minimal losses, more precisely, to the concentration of nitrogen compounds and phosphates. The most important role in this process in the future will be played by taking into account and correctly implementing the plants’ requirements for lighting, carbon dioxide concentration, and pH value.
Fighting algae once they appear is no easy task, so the main thing in this matter is to prevent their appearance! Along with live food, aquarium plants, snails, and fish (in the transport water), they enter the home aquarium, and if they find favorable conditions, they multiply very quickly. Hydra and planarians also enter the aquarium along with newly acquired plants.
Before placing purchased plants into the aquarium, they must be treated to prevent the introduction of algae, plant pests like water aphids, snails and their eggs, fish disease pathogens, and parasites. Never neglect this rule! Do not acquire any aquarium plants from aquariums where algae are present. Carefully inspect the plants before placing them in the aquarium. Check for algae contamination, and discard them if necessary. Aquatic vegetation is often a mechanical vector for pathogens of many infectious diseases in aquarium fish.
Stems always begin to rot from the bottom up. This is the first and most obvious sign of insufficient lighting. Under weak lighting, plants become pale, lose their lower leaves, and the stem becomes bare. At the same time, the upper part, which is closer to the light, continues to grow and produces many leaves. Plants try to get closer to the light, their internodes stretch, and their stems become thinner. The part of the stem located in the substrate begins to soften and turns into mush, spreading upward until the stem detaches and floats to the surface.
Aquarists often replant the stems afterward, and the same thing happens over and over again. When the lighting level is increased, plant stems react quickly, even if other factors are insufficient. In this case, you need to check whether other plants in the aquarium are taking up too much light and thin them out if necessary. You also need to make the lighting more powerful.
Carbon is a vital nutrient for plants. A lack of carbon dioxide causes a slowdown or complete cessation of plant growth, the appearance of deformed and stunted plants, and a sharp increase in pH. In some cases, it can cause them to fall ill. For example, a CO2 deficiency can provoke the so-called “Cryptocoryne disease”, when the leaf blades of these plants become glassy, soft, and begin to decompose.
Plants requiring bright lighting—Cabomba, Limnophila, Heteranthera, Myriophyllum, Nymphaea, Barclaya—require higher CO2 concentrations of up to 30–40 mg/l for growth, whereas Vallisneria, Hygrophila, Ceratophyllum, Java moss, and the water fern Ceratopteris only need 2–6 mg/l. Therefore, plants that require very bright lighting but do not receive enough carbon dioxide simply languish for years. There are also transitional forms that do not require very bright light but demand a high concentration of CO2 (some Aponogeton, Anubias, Bolbitis).
It is undesirable for the substrate to be too dense. This can cause the leaves and roots of plants to deform, especially young plants. The quantity and quality of the substrate must meet the requirements of specific plant species. The roots of large plants occupy an area up to 15–20 cm from the growth point (up to 35 cm in diameter). In this zone, processes of bottom organic matter decay occur, which are balanced by the assimilation of final products by plant roots. In this zone, acidification and the formation of methane and hydrogen sulfide do not occur.
Therefore, such zones are cleaned superficially, while areas without plants must be cleaned across the entire thickness of the substrate until the drained water runs clear. Inaccessible places should be stirred with a glass rod, and if gas bubbles float up, these areas must be thoroughly cleaned. Sometimes it happens that plants significantly slow down their growth or stop growing altogether. At the same time, they do not die and do not lose their coloration. This usually happens 2–3 years after replacing the substrate and means that all the necessary substances contained in it have been depleted. If root rot is observed in old aquariums, a complete water change and substrate washing are necessary.
Main causes of plant diseases.
List of plants for foreground, midground, and background. 
